The easiest way  to set up rear sets  and reverse the gear change, is to move the footrests back to about where they are in line with the pivot, and simply put the gear lever on back to front with no linkage, so that the rubber is  under the joint of your big toe. I wouldn't use clip-ons on a street bike - ace clubman bars are  a better option, and you can buy them with different offsets. You should make  sure that your hands are not forward of the steering head bearings when you are riding the bike - dangerous. Keeping the kickstart is always  difficult.  You need a folding  footrest, and a  folding  kickstart.  And  the footrest must have  a locating  detent, so it d oesn't unfold when you are kicking  the  bike over. If your footrests are only 25mm too far back, the bike will be horrible to ride, you should have some easy way of adjusting their position.  Have a look at a modern racing superbike, and make something that looks right  for your own classic bike.
The Dunstall rearsets  always looked cheap and nasty, and the folding bits of the footrests used to sag after a while and look very daggy, and I never liked the flat rubbers.  A knurled set of footrests with no rubbers, as used on an early  Ducati 250 or an MV125 always looked much better.