Experienced person with these matters -- Run Flat is generally heavier with significantly stiffer sidewalls which makes mounting a bear. The Bridgestone DriveGuard that I mounted several pairs of took a hydraulic tire machine and two men. They wear very well I typically got 36k out of them. As to which size to put on your bike I ran 205-50-17 on the rear when I mounted a Vredestein Hypertrac. I think the DriveGuard was 195. It does make a difference and it depends entirely on the profile of the individual tire. Some car tires are squared off where tread meets sidewall whereas other are more rounded. As I recall there is a Firestone tire that looks like it has right angles. If your tire is going to be a problem its going to happen where the "corner" of the tire meets the swingarm. Some folks have gently ground their swing arm for clearance issues but I opted for finding a rounder profile tire. The Vredestein is one of the most rounded tires out there and it gets great TireRack reviews. It typically only goes 24k miles though. The DriveGuards were squarer but cleared. Some will have a hard time clearing even in 195 size. A good number to look for is the tread width which tells you at what distance the tire starts curving away from your swingarm. Running at a low psi increases the likelihood of rub, but not much. Running high speed makes the tire taller and skinnier.
In addition to rub on the swing arm you need to get the tire past the differential and the tire likes to stick on everything on the way in. Find a Gallon milk carton and cut out two of the sides. Place these between the tire and the housing/abs sensor and the two pieces of milk carton will slide across each other allowing your UNINFLATED tire to pass more easily. You'll still have to work it in.
Lastly, you will need a tire pressure monitor because you will not be able to tell when your tire goes flat. And that can be bad. Very bad. Several threads on here about that and FOBO seems to be a good way to go. The garmin ones never lasted long for me.
I put a thread on here about rear tires on the front which you can search for. The Bridgestone BT46s are a good choice but a while back they redesigned the tire and the sidewall was much wider than before. 130-70-18 is too wide. Go for 120-80-18. You'll still have to check for clearance issues with the fender.
Bob