Idlers are different, life time has roller bearings, button head unit is bushing. Use 30wt engine oil in the LT units, "OO" grease in the button head units.
Don't have the answer on the dip stick.
I will try to find mine in all this lovely snow we have up here, I will measure it for you. that is if I can get to it, I am planning on starting it up on Sat, first time this year.
Thanks for the information, and I would appreciate it if you could
the transmission dipstick on this one is 21.5" from top of lid to bottom of stick. It is the round flat lid, original I presume.