Here is mine
I did a fair bit of machining to make mine fit. The first thing I did was to remove the bearings and cut the holes deeper to put two smaller bearings (thinner) but by doing so, I could use the stock Norton front axle. The bearings I used are SKF 6003-2RS.
Then I machined the backing plates a bit, I don't remember how much, but I could take measurements if you are interested. I had the speedo drive welded up but the aluminium is of low grade so there are some holes which I patched up with epoxy. The center was beefed up and a steel insert put in, if this is not done, the brake plates will squich and deform from the Commando axle and make them very hard to remove. The stock Suzuki axle is smaller and held on differently in the forks on a GT750 and does not force the brake plates inwards. To make it look nice, I painted the whole thing black.
I had this brake on my Fastback, looked nice, but it was not well set up, this time I'm doing it better and hope it performs as it should. I have the proper Suzuki front brake lever and the stock Suzuki brake cables so that should help. And yes, it is heavy (Il'l weigh it tomorrow)
I have it laced to a WM3 18" Sun rim from Bucchanan's with SS spokes. This whole assembly is going on my Featherbed based café racer.
Hope this helps
Jean
Here is a picture of a stock Suzuki brake.