Stoney, my friend, you do drive in 4H on slippery or loose roads. right?
if i have open, lock rite, welded, shimmed LS in the rear diff i run in 4H (on curvy roads) on loose gravel , ice, snow, mud.
i have watched for years as fellow wheelers unlock at the end of the trail but i wait till i am back on terra firma. i usually drive fairly fast and agressive and to me it just doesn't make sense to unlock the hubs on the (in my mind) the most dangerous section of trail.
a couple decads ago i was told by an old timer NEVER unlock the front hubs till you are on high traction terrain.
i used to run with a heavy footed crowd and shortly after that advice, i booting back from a trail head heading back on gravel to the paved road in a gasser 40. i had a welded in the back and the front was locked but i was in 2H. i took a section of the road at too fast and hit a bit of a wash board. the rear started coming around on me so i reached down and slipped the lever back into 4H and blurped the throttle. the front pulled straight again and i was fine, a bit shaken but fine.
i don't care if you run locked or open, my suggestion is run wih the front hubs engaged till you are back on dry pavement or solid dirt. with the Land Cruiser you can shift at any speed from 2H to 4H as long the front hubs are locked. this is a safe guard for on the highway in slippery conditions and other than minimal wear on the front end (think 80 series) and about 1 or 2 mpg loss in milage you have nothing to loose.
you can also think of it this way, you don't wait till you are stuck off road to lock the front diff, do you? no most of us lock the front hubs at the trail head since we know we might need the extra control and traction as we negotiate the trail, it is the same reasoning when it comes to traction issues in everyday life.
cheers