The bottom shield is what I suspected... it has some limestone and kaolin clay that has some copper powder/dust mixed in so that it dissolves slowly. Everything is held together with some thinned down epoxy. Dont be fooled with the idea that because it contains epoxy that it somehow adds to the waterproofing of the plywood. It wont. Epoxy will stick to the bottom strongly, but once the powders have dissolved into water, you are left with a porous layer of epoxy. Its as watertigth as a sponge as just about all these kind of bottom paints do. After a few rounds of bottompaint you need to scrape / sand the porous layers of leftover epoxy in order to be able to have the next layer of bottom pain stick to the bottom. ==> So I suggest you ask the company that makes it before committing to this solution the following:
1. How long will the antifouling effect last? In other words, how often do you need to reapply this product?
2. How many layers of this product can you stack on top of each other? This will give you the timetable for re-sanding the bottom.
3. Ask about the toxisity of the product for reapplying and sanding /sandblasting the bottom for you and the environment.
4. Ask about health precautions for these procedures (masks, gloves,... environment and groundwater protection... and waste disposal).
I am not familiar with US regulations but at least here there is a strong sence of the need to always consider the whole lifespan of a product. Thats especially important with products that are harmfull or toxic.
About the main issue... I am afraid those safetysheets provide some info about contents, but will not answer the main question. How long does it take to cure the epoxy to a point after witch its too late to rely on chemical bond? As both products you mentioned are mixtures of several chemistries, the only way to change the curing time chemically is by changing both hardeners in the hardener mix (and they have to be in exact proportions), so you are on the mercy of the product supplier. If you use a product like the West System you have several hardener options to choose from. This means that you can adjust the opentime to be suitable for your timetable.
Here is a proper guide to epoxywork...
https://www.westsystem.com/wp-content/uploads/GougeonBook-061205-1.pdf I have posted the link into the library section of the forum a long time ago.
The stuff i have talked about involving the open time. is on pages 31-33. The open time depends mainly on the chemistry used and temperature. You cannot change the curing time by adding more hardener, you just end up with uncured epoxy. But you can change the time by changing the chemistry (choosing a different hardener if such is available) or by changing the temperature. Cooling down the workplase slows down the process. Warming up makes the process faster. The main thing is to PLAN the process of laminating the hull, so that you have the time to put on the next layer without sanding. In order to plan timetables, you need the curing time. If you cannot get it from the manufacturer, you can make a test with what you got. Renns instruction on estimating when the epoxy is still able to form chemical bonds is good enough for DIY use. If you still can use your fingernail to make a dent, its still OK to add the next layer. You just need to know how long it takes from the mixing untill its too late, and have the proper safety margin to finish your layer in time. (and keep the temperature stable ).
Then the other matter... and the picture I posted about long term permeability studies by Cougen brothers. They have done studies about epoxy permeability and the results are simple. Good quality epoxy is way better that bad quality and polyester, and you need a thick enough layer of epoxy to do the trick of keeping the water out suffuciently. Thats why you need a thick enough layer of epoxy on top of the plywood before you add any antifouling.
I will explain this later with some links.. sorry gotta go again.
