West is a reputable company, I know guys who use their stuff - with great satisfaction - for boats. I've never used their products. I hear 105 is super fluid, which could present challenges. Like, you need to use tape to create a lip around the edge of e.g. a flat piece of plywood, otherwise the resin just flows right off the flat plane. That sounds too runny for my taste. It can probably be amended with a thickening agent. West probably sells that, they sell LOTS of stuff (I've browsed).
I've used Polygem (zoopoxy) and Smooth-on (habitat cast n coat) products. Putty in the former, brushable in the latter. Both are outstanding. Both are 1:1 two-part formulations. I can recommend either company; each as it happens makes brushable and putty formulations. I have posted here a little about my experiences with them. No build logs, just a little sharing.
Epoxies all require a catalyst AFAIK
. Maybe this is the hardener of which you speak? Whatever you wind up deciding, all I can see is RTFM and read it for comprehension. Follow instructions and you're good to go.