The ideal levelling system to prevent frame twisting would be a 3 jack system, as I see on only a few rigs. My rig's instructions are to level then extend, otherwise you have a large heavy weight suspended out to the side of the rig, supported only by the rig's suspension. My HWH system won't let you extend just one corner jack at a time, I presume it is designed that way so that it minimizes twisting forces on the rig by equalizing pressure between both jacks on one side, to some degree the same that your spring or bag on one corner will naturally deflect to minimize frame twisting.
Oh, yea, I now have a crack in my windshield that happened while in storage, with jacks retracted.
This thread should have been a poll.
Ole and Anne Anderson, Highland, Michigan
'02 Adventurer 32V, Ford F-53, ours since 4/08,Goodyears, Konis, SeeLevel, CHF
'84 CJ-7 , 5.3 Chevy, 3" lift, 33's, Detroit Locker, Fiberglas tub, winch, hi-lift