Q: What kind of sealant material should be used at the penetration points, between the flashing and the shingles, and for the Soladeck box?
A: Typically it is recommended to discuss this with a local roofer who can check out your site in person. Another avenue is to check with the flashing manufacturer, to see if they have an ideal product for use with their system. However, you can source a generic sealant from a local home improvement or roofing store. I might recommend a products like GEOCEL or similar. Check out this article to give you some ideas on sealants. Note that the flashing system purchased should cover you in this aspect, but adding sealant is definitely recommended.