moving on

Do you have the ability to cut spacers, drill the cones, cut the clips?

http://form1suppressor.boards.net/

Go there and do a BUNCH of reading.

If you knew EXACTLY what you wanted, I bet you could email DM telling him what it was you wanted with a paypal address so he could bill you and you'd probably get what you needed.  If you want to ask a bunch of questions....sounds like he is too busy.

You haven't found information on a 1.5x8" suppressor for 300blk? It's probably the most common size and caliber build, in the form 1 area, for a long while. The ASR mount has been integrated into a good amount of them. I believe this is why DM and another seller were making the adapters.

As said, the form1 boards will have the most info on this specific topic.
Plenty of, near identical, builds here.
Silencertalk will have a few threads on it.

Both here and the form1 boards will have retailers/suppliers, their products, along with weights and a good deal of dimensional info.

Your query regarding baffle material will be second only to spacing, and followed by specific clipping information.

ETA:
There's a thread, only 5 posts down, covering Zmachineworks.
Another 5 posts down has info on your material question.
Just the first page, in the "Build it yourself" section, will answer almost all of your inquiries.