I hadn't heard that Steve was ill......hope he makes a full recovery soon.
I haven't gotten back with "Craig" after receiving his e-mail ........ just giving them a chance to get the welding-jigs in along with those first sets of frame-casting from "Steve".
We both should have picked these up years ago before the exchange-rate went up......and I believe that this is one of the reasons for setting up a good frame-shop in the USA.......and the added advantage of better (read that as more detailed) frame-casting........"and" the ability for some custom-work.
After owning/riding a '57 Pan all over the USA, and then all over the available areas in Europe (pre-wall take-down).....I would still be a little hesitant on the ability of the older parts in the Knuck's engine to take no-lead gas (as you said all original) in this day and age of no-lead and then alcohol added to fuel make slight-changes to even the present-day "TC" "maps" if moving to a different area to get best performance.
Hopefully, you had the engine-builder incorporate most of the "up-date" into the engine as could be done........we use up-date a lot of earlier engines to "no-lead" valve-seats, valves/and guides w/seals as HD did with the last years of the Shovelheads......which made engines last much longer.
On the "off-set" springer.......what year Knuck are you building (?).........my last complete off-set springer went to a club-brother a few years ago that was building a bike.
Watch the parts coming out of Europe......there are a few people manufacturing early-parts......even to include early Indian frames, etc..
My best suggestion on locating an complete "off-set" spriner front-end would be the internet..........go from any of the MC Magazines ad-sections and then start e-mailing the shops ....... may come across one that way......and a WTB ad on some of the Forums may bring you one from someone parts-pile due to economy/"bills".........but again, just watch out for newly made springers (both painted and chromed) as they may be made overseas and were/are sold by "V-Twin".
Keep the rubber-side down.....and maybe I'll see ya' out on the highway sometime.
Regards, RichardS in MI.
US Army, Retired
Blanksguy2001@chartermi.net