I also have 20" 225/30-20 & i run 40psi & thats also what the tyre shop advised me to run.
I'm paranoid about my pressures cause i only have to lose a couple of psi & the rim is nearly touching the ground so i cary a digital gauge around with me, my last set of rims were 215/35 & often had a leak so thats why im so paranoid about my pressures.
I to have Tein flex installed a bit firm at the moment but the shocks are still on the medium setting until there run-in. so hopefully they will soften up a bit when i do change the setting.
I think most of the harshness comes from the lack of tyre profile.
BUT YOU GET THAT WITH 30 SERIES TYRES
