Rear shock fitment
 

I have a Santa Cruz Superlight and planning on changing the rear shock from a Float R to RP23 or similar. Im having a little confusion as to what measurement of rear shock I should be looking for.
I check out the eye to eye length, and it defiantly 7.825".
What im having trouble understanding is the travel length. Im not really too sure where to measure for that. Its either 2.25" or 2.0". I have a feeling its 2.5", because the measurement from the seal to the end of the lower bolt is so.
Ive check Fox's site and it says that Float R's in measurements 7.825" X 2.25" do not come as an aftermarket option. The closest aftermarket on is the 7.825" X 2.0". I know this is a new shock and is not the original one that came with the bike.

Can some one give a quick guild line as to how I can measure this the correct way (maybe a picture)?
Would I still be able to buy a 7.825" X 2.0" and have it fit without a travel decrease, if indeed it is a 2.25" stroke?

One way to be sure is: let all the air out of the shock, compress it, measure from bottomed out to all the way open. FWIW I've used a replacement shock temporarily that had different travel than the original and it wasn't really noticeable. Just make sure the eye-to-eye length is correct.