When I put the 9R22.5 tires on my wheels I was afraid to take them to the tire shop, They were just back from being powder coating and I didn't trust anyone to not nick them.
I did have the old ones and the new used 9R22.5 tires removed at the shop.
To avoid scratching the wheel use plenty of tire goop to start.
Lay down a moving blanket to work on
http://rides.webshots.com/photo/2062689850080251109FkJdHsI put tape on the tire irons, but would skip that step next time, it did not last.
But do use plenty of anti-freeze jug strips, about 2"x6" works well. Place them between the tire iron and the rim. (Also works well for protecting paint when installing lock rings on wheels, you'll need more)
Again, just throw the tire on to get the first side, stand back, hold the tire back side low and front side high just a little, take a running start and land and push it on the rim.
I had done it before, but was very pleasantly surprised how well it worked last six times, no prying at all for the first side.
Pry the second side on using the plastic strips as protection
No nicks or scratches.
Grigg