have you thought about changing formulas? my DS (now 2) was on S26-AR and i had heaps of trouble feeding him - so in the end i just cut the teats but had to buy new ones very very often.
my DS (10 weeks) also has suspected reflux so i did a bit of research and found "NOVALAC REFLUX". it stays liquid in the bottle and turns thick once it mixes with stomach acids etc. my DS is still using the same new born teats which is great! novalac is only available at chemists.

good luck