I just got a MH 6'6" bait caster that will be used for jigs, weighted and unweighted plastics and some spinnerbaits. I fish in grass. I use my 7 H for pitching and flipping and topwater frogs. So I have a heavy duty but do you think that 30lb braid would be good for the MH?

Yes. Tie a leader as conditions or lure type dictate, but 30lb braid is my go to on bc gear.

I have my flipping stick (MH) and frog rod (MH, but close to H) with 65 lbs, I have my cranking MH with 30 lbs, all the other MH gets 50 lbs. My rod for jigging spoon (M) gets 30 lbs as well.

On my casting set ups this is how I do it:

 

Cranking rods......20lb (one M, one MH)

 

Jig/worm rods.....30lb (one M, 3 MH's)

 

Frog/swim jig/spinnerbait rod......50lb (MH)

 

Flipping/punching rod....50lb (H)

 

Top water and jerkbait rod....20lb (M)

You will be fine with 30lb braid for your MH.