AR doesn't have any teeth, and she's pretty good with her food. But I do find she does much better with BLS; she will eat purees if she has to (ie, I don't have dinner ready in time ) but she eats more, and for longer when it's BLS.
Don't know if that's any help... hope you get the feeding sorted soon, it must be hard haivng to go into child care to feed him. Maybe the sippy cup will work?
Good luck