hello there mate most pellet break down times are fast i find that a pellet band you get abit longer time in the water best thing to do is buy some pellets drop them in glass of water and time them (break down times)you will find the best ones suited to you
if you are using pre drilled pellets the hole go s well big as it swells from the middle outwards so your boilie stop will just slip though the hole result no pellet on the rig try pellet bands they are a must