Honestly BigJohn, the mindset & skills you've attained as a blacksmith may serve you far better than any bicycling or gasoline engine experience - these creations bear little resemblance to your average bike when done and the engines... well... they're so
primitive that previous time spent tinkerin' on anything else may just confuse and befuddle lol
Yet they are
simple, a bit of courage, a touch of patience and you'll have the bike and engine figured out in no time - it's the need & ability to fabricate things that tends to trip people up, and that is something you've got. It's tru that blacksmithing and metalworking aren't quite the same, but they're dang close heh and that
ability is SO valuable in this hobby - you've a distinct advantage over those that are forced to rely on a hardware store exclusively.
A shiftkit is
worth the trouble, but yer right - perhaps not for yer first bike as you'd hafta pull it all back apart again and the time to ride is now! Still, it's not that difficult to install one and the instructions on SBP's site are quite good. I'd recommend riding the bejabbers outa the bike you've built and save up pennies & parts for a winter project - one season on a motorized bicycle and you'll be an "expert" jus' like the rest of us addled addicts