@Hark_Ptooie Yes all the XT600 forks look pretty similar (except the XT600E has a twin piston front caliper), I wouldn't think the fork springs differ that much between models and I have heard of people running XT600E fork springs in the DTR. The 3AJ is the Ténéré yes, I recommended them because I found someone selling a set on eBay for £20 (he'd fitted aftermarket springs as Yamaha managed to make the forks too soft an that bike as well).
I never liked the XT600E to be honest, I owned a Honda NX650 Dominator at one time and that was something of a disappointment as well, I think a well sorted DTR or KMX125/TS125R would give all those big singles a run for their money on tarmac as well as being a lot more fun off-road.