Understanding rear shock #s

[brmeyer135]

Question about rear shocks.
To start, the following link is good overall in understanding:  http://www.pinkbike.com/forum/listcomments/?threadid=136066
My question was the same as the last person on that page:
The eye to eye is proportional to the stroke...but, say a bike needs a 200 x 50
Does a 200 x 51 or 200 x 57 work for that bike?
Initially, I would think that any 200 would work and as long as you are longer than the recommended you should be OK.

[Carbon_Dude]

I would expect that if the shock travel were a bit longer then the initial compression, sag, would just be a few more millimeters and possibly one would need a little less air pressure.