A few quick comments.
- thinning epoxy with alcohol weakens the bond strength.
- I use West Coat Systems, so there is no added thinning, you must mix _exactly_ as described
- I do not agree with the thinning idea anyway. Soaking into the wood is adding a LOT of weight (that 3rd coat). What's the value? Yes the surface is tough/durable (but NOT stronger). If I were building a boat, I'd do it. For my planes, I want them light as possible.