Dimpling
 

Just out of interest I dimpled the same thickness material as the ribs with the tank dimple die set and the same material thickness as the wing skins with the normal 3/32 die and found that it looks like it fits together far better than just using the same dimple die set for both.
Has anyone had experience with doing it this way?
Thanks.

Dimpling
 

Yes and it works great. In cases where there are three overlapping surfaces, I've gone as far as using regular die on the top skin, tank die on the underlying skin, and substructure die on the underlying spar.

That's exactly what Cleaveland tool recommends in the description of the tank dies. I did that with my wing structure.

This is honestly the first time I have ever heard of "tank dies" and I don't recall reading in any build logs about people using them. Is it common knowledge to use tank dies? I don't mind buying them especially if it will help out in producing a leak free tank but I am just surprised nobody has ever mentioned them before and since I'm working on my tanks now this has my attention.

I found lots of mentions of them in the search function here at VAF, just never a mention in build logs.

Dies
 

+1
That's how most of my bird is built.

Or just simplify your life and use one set of dimple dies for all parts and surfaces.
I have been doing this since 93 and have built 10 aircraft, one of them and award winner at AirVenture.
I do not have the time now to look it up but a year or so ago I did a comparison between joints done with regular and the sub structure dies. The parts were cut and polished. The substructure dies result in a larger hole which ultimately requires more rivet to fill this hole. This, in some cases left microsopic but visible voids in the joint. There was no difference in how the actual parts fit together after riveting whether you used the regular or subsurface dies.

Really appreciate the feedback Gents. Lot of practical analysis. Good reasoning supporting all the methodology used, guess I'll have to use my casting vote on this one and then build on.