Anyone guessing a rate to fit someone else is just that.....a guess, right?
My guess is the .40. I'd guess .42 if Honda made that spring for that bike, but I don't think that is the case.
You might ask your parts guy? Like you can buy different rate springs from Kawi for Kawi, maybe you can buy different Honda springs for the XR?
The length will be what it is. Different riders have gotten different length springs when they are for the same application. Don't know the whys of that. My springs (from Honda via MX-Tech) are 532mm.
re: feel every root.
That's kind of the point of these springs. They can be stiff enough to do the job, but because the are so much longer than the oem springs they are more linear, so the little stuff is something you don't feel at all.
Well, there's the plus of taking out those stupid (Dumb! Moronic, even!) oem spacers that get you something like 35mm preload.