Hi Big Blue,
What tools do you need? A double cut flat file, a bar of soap for marking the high spots,
and a piece of about 180 grit abrasive cloth.
Check some of my older posts on fitting fins. Do a search on "Fitting Fins".
If you use the soap (rub it on the fin root to see where the root is tight in the fin box)
it should only take a few minutes and a few strokes with your double cut file to get the Chameleon to fit into your isonic.
The abrasive cloth is simply to fair in where you file off the high spots.
Hope this helps,