[65Bowrider]

This thread has been incredible!
I still need to check to make sure the mat does not have styrine.
Otto - won't be ready for the job this weekend, so you're safe ... but hopefully by next weekend we'll have all the material & be ready.
Vinegar is a good idea ... Costco sells by the gallon.
Disposable suits is also good & cheap. Already picked up 100 latex/powdered gloves
And I have plenty of contact paper ... I like the idea of easy cleanup.
Strict - OB sleeve? I like the idea ... can I use the plastic bags newspapers come in? How did you protect the thru-bolts from getting resin on them & sticking?

We've heard of the technique of making huge clothespin type clamps & using about 6 to slide over the transom to push it all together. Using 3/4 ply approx 12" wide & long enough to reach the transom bottom & then notching out the expected thickness of Coosa & fiberglass layers. If it doesn't work, want to be prepared for the thru-bolt method.

Our total planned layer of construction is: on skin, 1.5 oz mat, 2 layers 1708, 1.5oz mat on Coosa, Coosa Board (clamp & let all set up), then 1.5 oz mat on inside Coosa, 4 layers of 1708. Let set up.
Hopefully that's enough to beef up for twin engines. (basic layer construction recommended by Hermco)
But he didn't provide a video of the "how to"... so all your tips have been tremedous and I really appreciate your taking the time to post & share. Thank you.