If your LO had issues with solids, when did you start weaning from formula/breastmilk bottles? Did you still start whole milk (or another kind of milk?) at a year?

My almost 11 month old LOs have trouble digesting solids (possible delayed gastric emptying although they have not been through testing yet). They have plenty of interest, but their systems can't handle very much at a time. My kids nurse and take formula bottles. I plan to nurse until they seem ready to stop, but I'd love to be done with the hassle of making formula bottles. However, right now they get 99% of their nutrition from the formula. Without solids, I doubt we'd be able to get them off formula.

We are working with a GI now and will follow his lead regarding bottles, whole cow's milk, etc. but I'm wondering what others experienced. So when did you transition to whole milk/off bottles with youR LO and what kind of issues did they have with solids?