Here's what I'd suggest: Cut 3' of 4" Eternabond into two 2" strips. Locate the rafters where you wish to install the solar module. Place the tape across at least two rafters and this will be the location of where you mount aluminum angle as brackets. Drill the aluminum angle pieces at the rafter spacing measurements. Place on the tape and drill into the rafters. Attach the aluminum angle pieces on top of the Eternabond strips with #12 stainless screws in three locations. The module can now be fitted with either short angle pieces in the mounting holes of the panel or Z brackets. Fasten the brackets on the module to the brackets you've installed on the roof.
You could also attach all the aluminum pieces on the ground and then fasten onto the roof. Your choice (depends on your measurement skills).
If you proceed like above, your solar panel will be held very rigidly to the roof and the Eternabond tape will seal the screws as they are driven through the tape. You will likely squirt on a bunch of sealer onto the screws (everybody needs to make their project look like a Kindergarten craft affair) but it isn't needed.
FWIW, I have a 60" module with a four-way tilting mechanism attached like above. It sits for 6 mos. of the year with the module tilted in all kinds of wind and weather. It is like it's welded to the aluminum sheet roof.
Good luck with the installation.
