Many thanks to all of you for your considered responses and advice, greatly appreciated. Unfortunately the threads are largely non-existent so there isnt anything left, to try and clean up.
I would also be remiss in not saying that although i have owned/ worked on multiple years/makes/models of motorcycles almost all my life, i am both grateful for, and extremely impressed with this forum, the wealth of information and the willingness of fellow Douglas enthusiasts to so kindly share their knowledge. Getting a belt drive Douglas (now 3 of them!) was a dream come true for me and this forum has been invaluable in realizing/restoring that dream.
Many thanks,
(if anyone knows a source for the required 1 1/4 BSCY die, for inlet flange, i'd appreciate it).
bryan