Congrats on yet another Franken 2201.50. I've been after a project like this for almost 2 years now.
Installed the gen SEL's and clasp, case back, crown and tube and removed the outer AR on the crystal....then a much needed Rollie part came around and I sold it.
A week ago I thought I'd have it back in my hands to finish but alas...it made it as far as my Post Office and vanished.
I'm not sure about the HEV but as has already been mentioned, the trick to the gen tube going in the case is clean, clean, alcohol clean prepping and maintaining alignment while the tube is curing for 24 hrs. ( I used marine epoxy and it seemed to work well)
IMHO the gen SEL's, clasp, tube and crown are immediately necessary if you're planning to wear it right away.
The tube or crown threads strip out prematurely as does the clasp locking mechanism.
And the gen SEL's will eliminate that huge gap between the last link and the SEL
![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)