Having done another 230 mile trip today from Dublin to Belfast and back, I must say I am absolutlyfantasticallydelighted with my Progressives. I have 440 standard 12 1/2".
I know there are other options and makes. Hey, there is always more than one way to skin a cat, but whatever floats yr boat. For me, these are the dogs bollocks...
There are lots of Progressive Options for the Rocket....
http://progressivesuspension.com/appview.asp?AppsNumber=5405
Applications
TRIUMPH
Rocket III
04
412 Series
Standard 11.5" : 412-4202C
Standard 12" : 412-4229C
Standard 12.5" : 412-4209C+
Standard 13" : 412-4213C
Standard 13" : 412-4213C
Heavy Duty 11.5" : 412-4230C
Heavy Duty 12" : 412-4234C
Heavy Duty 12.5" : 412-4219C+
Heavy Duty 13" : 412-4221C
418 Series
Standard 11.5" : 418-1003B/C
Standard 12.5" : 418-1012B/C+
Standard 13" : 418-1013B/C
Heavy Duty 12.5" : 418-1019B/C+
Heavy Duty 13" : 418-1020B/C
440 Series
Standard 11.5" : 440-4202B/C
Standard 12" : 440-4229B/C
Standard 12.5" : 440-4209B/C+
Standard 13" : 440-4213B/C
Heavy Duty 11.5" : 440-4230B/C
Heavy Duty 12" : 440-4232B/C
Heavy Duty 12.5" : 440-4233B/C+
Heavy Duty 13" : 440-4221B/C
for finding out why the things work the way they do... or not
Fantastic explanation of suspension set ups.
Suspension Tuning Guide
http://www.sportrider.com/tech/146_0006_susp/
AND
Suspension Setup
http://old.bemsee.net/tech/setup.html
AND
http://www.vtwo.demon.co.uk/firestorm/suspension.htm