Hardtail huh? Those are known as "barhoppers" cause that's about as far as you can ride on that hardtail
Added a handshift? I guess a foot clutch when along with that? You're going to have fun building that bike. Do you plan to mold the frame any? If so, use epoxy and glass beads for filler on a sandblasted frame.
My first bike was a 165 Harley 2 stroke (made in Italy), At 15 Dad got me a "real" bike - a 1955 FLH panhead, ex-cop bike from Memphis, still had the black 'n white paint job with red lights. That bike had the handshift and "suicide" clutch. They were called suicide clutch because the design was to press clutch in, and it hold in place due to spring tension. The real world was with vibration from bike (yep, Harley's vibrated) the clutch would slowly release and away you'd go before being ready.
In the late '60s (68 or so?) I built my first "chopper" - extended forks, put a King 'n Queen style seat with tiny rear fender on that hardtail. Wife and I rode it first time, came home and designed a spring assembly under the seat so it would ride better than that hardtail frame.
During the '70s while in college we built several choppers with full molded raked 'n chopped frames, Been on bikes most of my life. Started riding Goldwings as an "old man" around '97. Sold my last 'wing couple years ago since It'd got hard to get my leg over that high seat, and didn't feel I could pick the bike up if it fell over.
Bikes have went the way of my sailboat (lived aboard about 25 yrs) - a past life.