I am going to spool my new spinning reel with braid and looking at putting on 20lb or 30lb. I will be fishing for bass and saltwater inshore reds/trout, my question which lb test should I use?

I would go with 20#.

Or even 10. One of the pros down in Florida mentions he even catches pretty large tarpon on 10 without any difficulty. But, he spends most of his time taking his clients out to the flats and sight fishes for Reds and other fish common to that space.

Brad

30lb Power Pro Super Slick, or Maxquatro

Power Pro Super Slick in 20 is my favorite. I use it on pond bass all they way up to inshore reds. Never a problem. Go 30 if you plan on using it in heavy cover. Can't go wrong either way!

Sufix 832 .....#20

I like #30 power pro, I add about 6 feet of #12 trilene when I want to downsize to small baits and cloaking.
good news is when ya get hung up the trilene will break before the braid..

I typically fish PowerPro 30# on baitcasters and PowerPro 20# on my spinning reels. Only reason for the reduction to 20# is my spinning reels are only used for topwater. 30# is a small enough diameter that it acts like a 12# mono of the reel, but is incredibly durable. This big yellow cat maxed out the Boga Grip's 30# scale like it was nothing! Fought him for half an hour with several long runs and muscled him up. The PowerPro had a little rub on it, but wasn't even close to breaking!