I also had a very heavy babe (I now have a heavy toddler, lol!). I didn't have this board at the time or know about my carrier options,
but there are several I've heard great things about.
One is the babytrekker, which seems to have good back support, and adapts (will work on your 2 month old but goes up to toddler weight on the back...).
I've only really used an OTSBH, and I agree that something adjustable like that allows you to have her whole weight tight against your hips and chest, not 'hanging' from your shoulders or back, if that makes sense? Also I like the padding with how heavy she is, though its bulky it's worth it to me - I still wear her in it on my hip at 16 months, nearly 30 lbs.
enjoy your babe,