by putting the whole thing in the oven it all expands at the same rate. This method works for just the crankcase prior to dropping the bearing ( which you put in the fridge before hand) in on assembly.
I'd use a heat gun around the bearing housing.
I take it you fitting new bearings after using a hammer on them.
The puller fits over the pinion gear and pulls off without heat....well it should do.
On the 650s the three gears have dots that line up for the cam timing with one keyway on each, although I have ones with 3 keyways that require dial guages to set up...
Earlier models have a timed cam breather but I'm not sure on the 750's.
Have fun with your Triumph.