It is double row
good move in my opinion :) my double row was a press fit i havn't used locktite on it yet, i did intend to when id tried it and all looked well, its done some hard work so far and iv had no issues with it, i do get a kind of harmonic ripple in the finish when i use a fly cutter in aluminium but it performs way above my exspectations and the ripple may be being caused elswhere ? (gantry sides maybe)
80mm spindle
ah, with you now :)

i'd be shit scared of getting the shaft stuck only half way home using heat... that shaft will soak the heat out of those tiny inner bearing races in no time

i would think that runout issues of bearing misalighnment (im pretty sure you will get some no matter how hard you try) would be massive compared to any runout you get with the wet n dry inaccuracies
the advantage in my opinion to the microscopic missalighnment you will "probably" get is that it will pre load all your bearings to some extent and stop any of them free wheeling and skidding
However........ im no exspert and only guesstimating with this stuff :)

skim a tad off between the bearing seats
nice