I am nursing my 34 month old and 11 week adopted baby. I pretty much have worked up to full supply for the baby.
I started pumping and storing much earlier than you did. (Then lost half my milk to a freezer accident. Get an appliance lock in the child-safety department to prevent this.)
My son nursed about 8 times a day before the baby came--he probably still does if I let him. However, I don't know how much he actually got as I put on 15 pounds because I didn't cut back my food when he cutback how much milk he actually ingested. (I didn't want to diet so the weightloss wouldn't interfere with my milk supply.) I was taking domperidone before we got the baby and it helped my milk supply a lot. Check out asklenore.com since they're all about adoptive nursing. I found the Canadian dom to be better than the online stuff you can buy out of asia or wherever it comes from.
We got the call about our baby when she was 1.3 hours old. I first nursed her at 6 hours of age. I have been weighing my baby weekly on the same scale to make sure she is getting enough milk. She is growing on her curve.
The first month I used a supplementer and she only needed 1 to 2 ounces of extra frozen milk each day. At the end of the month I tried going without supplementation thinking she would do what any baby does during a growth spurt and make me make more. The first 4 days we were fine. Then she got really fussy every afternoon, and I would calm her through those spells. However, by afternoon 4 I couldn't take it any more and went back to supplementation.
I never liked taking fenugreek or blessed thistle, so I stopped them early on. However, after above attempt at stopping supplementation, I was desperate for another answer. Someone recommended mother's milk tea. I tried it and it seemed to work, but I felt like it wasn't full guns for me. Then I read about goat's rue. I found motherlove brand more milk special blend. It took a couple weeks for it to really kick in, but I am pretty much now nursing without extra supplementation. If my toddler nurses a lot, then I am more likely to need to supplement. I also try and get up in the middle of the night sometimes to pump. I can often get an ounce or two (I was never a good pumper anyway. Only pumped 2 ounces even when my biobaby was 6 months old.) I save this milk for use during the following week so I don't have to use my frozen milk.
Everyone in my world has been so supportive of me and how well I've done from the start with one exception...the only person I know in real life who has adoptive nursed. It didn't work for her (she never got up much supply and had to use donated milk from milkshare.com. This is where we actually met as I donated milk to her first adopted baby.) Every time we communicated she just railroaded me with negatives. So, if you've got someone like that in your life, ignore them. She had me in tears. She mentioned my baby could become failure to thrive. It was awful. I am 11 weeks into this and am finally at full supply. I use the free sns short-term supplementer the hospital LC gave me. I just wash it with soap and water. I was going to get a lactaid, since they seem superior to sns, but the sns has a slower flow and I want that so I get more stimulation.
So, my recommendation is to get domperidone from Canada and pump multiple times a day (if you can with a 3 year old underfoot.) Also, store in small amounts. The bags I have with 4 and 5 ounces are difficult for me since sometimes she only uses 1/3 of an ounce at a time. In 1, 2, even 3 ounce amounts, I can break off chunks to thaw. If your baby ends up needing more milk this will be a waste of freezer bags, but that seems better than milk that's difficult to use when you need it.
I'm finding tandem nursing to be much more difficult than I'd read. In part because my supply is so borderline. I want my toddler--who is still full-time into nursing--to have as much nursing time as he wants, but I don't want the baby to lose out on milk so I look for ways to distract my son which is really painful for me. Bigger than that is he wants to play with the baby while they nurse together. The only time I allow this is at sleep time, except then he keeps her from falling asleep. Read adventures in tandem nursing which has a great chapter on adoptive nursing.
I think this is all disjointed, but I wanted to share a lot of info with you and I'm worried naps will end before I can finish this. You can pm me if you'd like.
Adoptive nursing is wonderful for all the reasons you know. I pumped for 28 months straight--first to make sure I had enough in the freezer for my son (in case there was an emergency and I couldn't nurse him,) then to donate to someone else's adopted baby, then to save up for my adopted baby. I was getting so burned out in the end. I know my husband thought I was nuts for all the adoptive prep I was doing. Now it's all just an exhausting memory and I am so happy to be fully nursing my baby. So, keep up the work, consider my suggestions, and wait for your little one. I sent letters to obstetricians around the state saying we were looking to adopt on Tuesday, August 5. On Sunday, August 10 one of them called us and we met our baby. Look back at my prior posts for more info.
Also, taste your milk to make sure it tastes good after storing. I have high lipase and my milk is awful 24 hours after I put it in the fridge. Fortunately my SIL said babies have different tastes than we do so I didn't dump the milk. Turns out my baby will drink it. However, I had to scald my milk for months to prevent this from happening since I didn't know if my baby would drink it or not.
Anyways, sorry again this is disjointed. I'll flag this in case you respond or you can pm me. Good luck.