Time for another update, the frame is off at the paintshop, so attention turns to wheels.
20 inch x 1 3/8 inch (451) rims in 36h drilling are tough to come by. SJS does some 28h but I couldn't get the 28h SRAM hub and already gone with the 36h version.
So all the way from sunny Florida a pair of Sun-Ringle CR-18 rims - I could only find black. Almost perfect except for the muppet in customs who cut open the box for a nose around and resealed it with his metal knife inside, leaving a couple of small dings! Nothing too bad though.
For those who are interested, some measurements. The SRAM hub is just about symmetrical so well designed for a strong wheel. Hub diameters I make 68.5mm and the centre to flange about 25.5 mm. The rim ERD measures 441 mm as given in the catalogue. I had heard that these can be a bit variable so all good there. Weight is about 400g so pretty strong and light.
Small spokes are also a bit scarce, again SJS has a good range of British made stainless spokes, which stand out from the iffy stuff sold as BMX spokes, but for the back wheel I wanted a familiar brand. Decided on 196 mm Sapim Leader 2 mm plain guage for a 2x build, as I certainly couldn't find any butted spokes in this length. I went with 2x cross as I was concerned that the spoke angles entering the nipples might be too extreme given the large flange hub and the 36 h drillings.
Ready to build up...