Fitting Tank Baffle

[alpinelakespilot2000]

I'm riveting my 2nd--and LAST!!!--tank baffle this evening, hopefully. On both of my tanks, however, when I test fit the baffle to the tank after all the ribs have been riveted, I've noticed that the tank skin has a tendency to "rack" a little bit once the ribs are riveted in. It's not bad, but the result is that I can get either all the top skin-baffle holes to line up perfectly or all the bottom skin-baffle rivets to line up perfectly, but not both. My "solution" on the first tank was to rivet the top skin-baffle first since that is what I'll see later, and then try to get the bottom skin-baffle rivets in as best as possible. The bottom rivets had to end up going in at a SLIGHT angle, leaving them close to, but not perfectly flush. While many of them squeezed in well, some are not as flush as I would like.

Has anyone else had this problem? Any suggestions so that I can do it a little better on my second baffle?

Thanks.