The Shimano hub should work fine. I had a 3cc version that I rode for years with no problem, it even used a nexus bell crank when I couldn't get the original kind, except 3 was 1 and vice versa but it was fine. It may still be in good shape somewhere. On those, I put light oil right down inside the axle where the shift rod goes.
While waiting for my wheels to finish, I tried a longer bolt with an extra spring on the fork. The spring is from a seat and the bolt is one I used to widen the springer previously. These Chinese springers use the same bolt as the spring and pivot bolt. I think the front will float even more now with the extra spring, the factory setup doesn't allow for forward motion, it just stops at the rubber grommet. Now it will float. These are called knee action springers. So now the knee can bend backwards too. That might be good or bad, a road test will tell. I hope the front tire won't contact the frame when I hit the brake.
While waiting for my wheels to finish, I tried a longer bolt with an extra spring on the fork. The spring is from a seat and the bolt is one I used to widen the springer previously. These Chinese springers use the same bolt as the spring and pivot bolt. I think the front will float even more now with the extra spring, the factory setup doesn't allow for forward motion, it just stops at the rubber grommet. Now it will float. These are called knee action springers. So now the knee can bend backwards too. That might be good or bad, a road test will tell. I hope the front tire won't contact the frame when I hit the brake.