Welcome to the forum first off. I think you'll find lots of information here. I changed out my rear to a 180/55 Dunlop (D220) without too much work. The shop I patronize machined the caliper and added a left side spacer to center the tire. Still run upper and lower belt guards and stock belt with lots of clearance. Check out the "Deuce Owners" thread under the Softail Family Forum, there's lots of conversion talk there.
It was my understanding that you could mount only the SE180 on a stock Deuce rear rim without mods. Any other 180 had to be mounted on a wider rim I thought, in addition to using spacers. I just changed to a 170/60 Metzeler and am impressed with the difference in ride and handling as compared to the stock 160.
BTW, I'm originally from North Carolina, and wish was back there riding. Too many crazy drivers out here in California.