In my @18 year experience with Crystal, formatting Excel exports has always been problematic. I can make a couple of recommendations, though, to help eliminate some of the merging that may be distorting the size of your page:
1. Don't use lines. In general, lines don't export (except, I think, with Cross-Tabs), but they do cause additional columns and rows.
2. Don't use the entire width of the page - make it a bit narrower than what will fit between the margins.
3. It sounds like you've made sure that the columns all export cleaning. However, you should also make sure that any other objects on your report - title, page number, etc. - outside of the main data also line up - for example, I usually set up the report title in the Report Header, line up the left side with the left side of the left-most column and the right side with the right side of the right-most column. Everything should line up. Also, I make sure that I don't mix text sizes within a row. So, for example, instead of lining up the top of the report date with the top of the title, I'll put the date on the left-hand side above the title with the bottom of the date lined up with the top of the title.
4. Make sure that in "Size and Position" all of your objects have a Y value of 0 and then push the bottom of the section up to the bottom of the fields in that section. In other words, eliminate blank areas at the top and bottom of sections, using "Can Grow" if you have data that will expand to multiple lines.
-Dell