I make baby and toddler quilts for Project Linus for our local chapter, and they aren't picky at all about sizes. In fact, our flyer states:
Blanket sizes:
Baby- 36x36 Toddler- 35x40
Child- 40x60 Youth- 45x65
Teen- 50x72
These are approximate sizes and you certainly dont have to stick to them exactly just try not to make them too small
or oddly shaped...
I hope this helps...I try to size things so they fit my batting and backings!
Laurie