Use the lightless weight you can get away with! You want it to barley fall threw the cover instead blowing threw it and having the bass chase it down. you want it to barely break the surface of the Matted vegetation and give the bass a easy meal!

I used to use 3/8 most of the time but, I have recently noticed myself using 5/16 80% of the time now. I think it was just getting better at feeling my bait with that lighter weight. I'll drop down to 1/4-1/8 on baby brush hogs/senkos

As light a weight as possible....just depends on the type of cover.