Yeah, the 19.5's can be kind of spendy. FWIW, I bought some 16" recap mud tires from Treadwright and have been pretty happy with them; they have 225/70r19.5's for $109 and 245/70r19.5's (in a more offroad tread pattern) for $119. Let us know how the 17's work if you get them.
Some of my crap:
1963 C-30 flatbed dually 292/SM420
1965 C-10 LWB fleet 250/column shift 3 speed
1965 C-30 9' stepside 250/SM420/4.10 gears (my DD)
Website I made for my crap:
http://www.66submarine.com 
