I had full pretty wild spec ALS, 23psi held by just revving it out of gear and letting off the gas, 28psi or so on the overrun when letting off throttle from a full boost blast, very slowly dropping a few psi.
That was with a T34.

But even mild ALS what i used to have when on greens was good, its the time from vac to boost that seems to make the bigest difference