What you want to do is to split the tank into quarters and put a separate sheet on each
for example, my 4x2 foot T8 needs 2 sections of 2 sheets, and 2 sections of 3 sheets
And since I'm sure that made no sense here are some pictures:
This makes cleaning easier and wastes less paper towels. Besides that, and the fact that if you are using a UTH you will need to adjust your thermostat... things shouldn't be any different.