The frame horns on mine were never centered. And with the shock offset on the left for belt clearance...
My rear fender is mounted via a left-over 1970s Jammer headlight mounting bracket. And it WILL pivot in the mount if I don't have a support from the exhaust tip to the muffler (VN800 reflector bracket for now). It will be a moving fender (think Kawasaki Drifters) later this spring... Of course, I run a full fender (FLH, Shovelhead era). And a seat based on the stock pan.
Low end bike, don't expect nice welds or perfectly straight fittings. Or fully welded brackets. Do expect the shifter linkage to bend and/or snap (pot metal).
Looks good so far.
Sprung seat that fits? K-model and early Ironhead Sportster spec, the one from V-Twin Mfg is just right, spring mounts are the same width as your stock seat mounting tabs. Make a cover for the top of the frame, Savage electrical parts are NOT water tight.
If you look closely enough you can JUST see the fender mounts, maybe...