Heck, George -- take along a handful of (big end) sprockets and have at it. They're easier to change than the small one. If stock is 45 -- get a range from say, 42 or 43 and up to about 47. Maybe even just get sprockets every other size from 43 - 47. If you can get a good price for buying them in quantity -- get yourself a 42 or even a 41 and plan on going through the lights in fifth - just to see how it runs that way. Not a big deal to change sprockets out there, so don't stress too much.
Sorry to be of little help. See you on the salt.
