Sounds like your plan is a good one. I don't know the system three product line, but I do know that you'll get better absorbtion into wood fibers and glass fabric with a bit slower epoxy. I used a fast hardner on a glass job once. The epoxy starts to thicken in minutes and that viscosoty change inhibits the absorbtion. It makes you work fast and/or have to mix tons of little batches. I could actually see a color difference where the wood absorbed more when the epoxy was thinner.

I warm up my epoxy good before sheathing jobs which lowers the viscosity but also makes it kick a little faster.

Go with a middle speed epoxy.