Suggestions for robust gutter mounts for self built roof rack?

I'm looking to build my own roof rack for my ambulance. Probably out of 8020. When I did this on my van build, I used unistrut that bolted to the van specific adapters. For the ambo, it's got gutters so I'd like to just mount to those vs drill holes in the roof for stuff like solar and possibly an awning of some form.

Any one know of some off the shelf gutter mounts that just have bolt holes I can bolt my own structure to?





You might look at truck upfit suppliers. Adrian Steel is what mostly used at my job.
They make all shape & size of gutter clamps. Being an ambulance body, You probably have to specify by dimensions rather than what fits ”xyz model Ford van”