The way you do it now seems almost easy and straightforward
Looks very familiar and without the body it is indeed even more easy to do.
Be carefull how much you shave off the bell housing though. I did leave a few mm before the second rib on the bell housing and you will need that with the height of the TO bearing being what it is. Leaving one or two mm more then I machined off might be even better still. So, instead of the appr. 1 inch, make it 20mm or so?
Also check the splined pinion shaft: with a type 4 crank being hollow the first part, you may not need to have the shaft shortenend at all. The length of the splines could be a little too much/long, but that depends heavily on the clutch set-up you will use.
Greets,
Walter