Temperatures for bottles
You need to fire higher or longer at your chosen temp. Temps. for bottle glass is similar to that for float glass. For me this means 835C.
You also are getting devitrification, so you need to clean the glass very well and add a devitrification spray, either purchased or home made.
You will have lots of stress in the resulting objects, as the glass from different bottles, is likely to be incompatible to some extent.