Booster and Convertible questions

[npl]

I have two questions about boosters.

1) Is there a booster available in Canada that will fit in the back-row centre seat in a 2006 Sienna. The rigid buckle stalks make the gap really small, and my Graco turboboosters don't fit. I'm trying to get 3 boosters in the back row.
2) My 10yo is husky, but not that tall. He finds his Graco turbobooster too narrow in the seat for his hips. He's too short to fit in the back row of my Sienna without a booster, and the captain's chair in the middle row is used by another kid who is also too short for that position.
Can you recommend a more roomy low-back booster (the backrest of the tbb is too short for him). I do have a Nautilus, which I could use backless, if it has more room.


Here's are my questions about convertibles.

My average-sized, 17mo dd is riding in a Graco Snugride 35. She still fits height-wise, but probably has a couple more months at most. But, she has no leg-room and pushes with her feet against the seat-back which makes it really hard to get her to sit down and buckle.
1)Will a convertible give her more leg room?
2)Which convertibles work well in a 2006 Sienna that are good for leg room, and don't take up too much space front-back when rf? She has to ride behind dh who needs the seat all the way back.

Thanks!

[DahliaRW]

It is very hard to find boosters that fit in the middle back.  I've heard the harmony literider and the recaro probooster do, but haven't tried them myself.  And I don't know if they are available in canada.  Sorry!

As for convertibles, the SR35 has a lot of leg room, a convertible might give more, but not a ton.  I have a graco myride behind the driver in my '09 sienna and it fits well and leaves plenty of room for the driver.

[npl]

Thanks!

Any other suggestions of seats that will work well in a Sienna (06) with the driver's seat all the way back? I need to keep her behind the driver's seat, but I can put the captain's chair all the way back, because my smallest kid sits behind her.

DD is average sized - 50th centile in height and weight for her age. I have a Nautilus for when she goes ff, but at 17mos, that isn't for a while. Also considering using Nautilus as a backless booster for my 10yo ds, who finds the graco turbobooster too small in the seat. That will then probably hand down to ds6 as a booster, so I'd like a seat that works for a while as a ff, just in case we need the Nautilus for a while longer.