Personally, I like the idea of removing the washer and makING the front axle engage only by the switch on the dash. That gives you high 6, low 6, high 4, and unlike stock trucks it also gives you low 4.
And running low range 4 in reverse would seem to me to place less strain on the transfer case than low range reverse 6.
However, less stress is not the same as tolerable stress.
"Some say".... let's see them demonstrate it. Condition's as follows - dry pavement, pulling another 5ton with engine off and springbrakes engaged. If it does not break, then at that point I'll be convinced. (That isn't a very demanding test either, in the scheme of things )