I wish I could give you the majic numbers for price,...but I can't. What you neeed to do, is figure up what it is costing you (ALL your costs). Then, with the amount of fuel difference, add a surcharge to this. With a nice letter, I thing most of these people will understand. ZI agree with your friend that you should NOT do as a general price increase. This just seems like it was a "lying in wait" tactic. I hope this helps.
Thank you, Dad - for always being the dad that you were. You truly are my hero. You always were.