Hello Bradley ,
Good project , I think 19 inch x 400 tyres look good on bobber type bikes although mine has 19 rear and 18 front , may change to 19 front later !? (also looking for Junior Scout tank) .
As for rear brake , you should look for drive and brake on opposite sides as is original , I have seen brake and sprocket on the same side but hooking up to the brake on the right looks wrong and awkward !
The original outer band works well and I've never had any bad experiences with them . 741 brakes are good too especially the rear .
Attach pic of my 101 bobber showing how the wheels look .
good luck , keep us informed of progress . Ken
PS , also attach pic of my 1922 Chief with 19 inch ali rims which look far better than ''English steel rims'' , they look more like the old Kelsey Hayes rims .?