You are correct on the press fit. I've pressed enough of them out to know they have no chance of coming out but I am going to groove the bottom for an external snap ring in case. Every one I have done needs a big frame press and comes out with a bang. The bolt on top to load the bearings has no chance of pulling the stem out and then the triples are holding it in place with pinch bolts. I don't have a press but my buddy does. I wish I did because you really want the lower bearing in
To get the measurements to machine the top and the length is critical too because it can't be too long or the bolt won't preload the bearings. I might machine up some dummy bearings from aluminum that slide on to use for mockup.
I really think the ninja frame is ideal. It's nicely designed and has built in protection already easy to also adapt crash bars that would bolt right up.
With the parts I'm making it's going to be relatively easy to adapt the running gear. I think you know how difficult it is to make a custom frame but I'm waiting for you to show me the way
quackamole frame is sweet for sure but thats a ton of work. I'm designing this bike with the idea that someone can take my drawings to a machinist and get the parts made, and the only tricky bit might be that I plan on bending steel to finish the subframe and thats hard to dimension.