Ok, so this is turning into quite the cluster f**k.
Finally got around to trying to make up lowers. After not being able to find the 2321-0038 at Motorcycle Superstore, I just ordered for the 1800 and got MEM9890 which don't fit. Too small. J&P Cycles says that part number should be MEM9954. Google 9954 and find spec's at Parts Unlimited - says 9954 fits up to 55mm. Won't fit. Too small.
Can't find a simple part number Search function at the Memphis Shades site.
So I google 2321-0038 and go to Dennis Kirk. Dennis Kirk says 2321-0038 fits C50, but no mention of the T. The picture at Dennis Kirk shows part number MEM9891. Parts Unlimited doesn't say what size forks MEM9891 fits. Search 9891 at Dennis Kirk and it says it fits C90T. Memphis Shades says the C90T has 69 to 78mm forks. Won't fit. Too big.
I'm going to ASSUME Dennis Kirk just has the wrong picture to go with 2321-0038...
Can you just imagine how complicated I could make a BIG project?!?