635 Thin Epoxy questions?

Good morning. I have been working on my mill, tubular steel structure. Once assembled and aligned, it will be cast into a block of simple e/g (for the base up to the y-axis rails), and the column will be filled. Being conservative with my mox ratios (18-20% epoxy by volume), I figured up about 5 gallons of mixed reson should do the trick, depending largely on the final dimensions of the base. The filled portion of the column will be a 4x8x.375 square steel tube. The base is 18x32 horizontally, and I will probably make it something like 12" tall but with a "hollow" core to save a little weight and epoxy.

1) The USComposites website shows using their fast (4:1) hardener has leaving the most rigid material once cured. So, that is good, right? I also read an anecdote in the big EG thread about the results using the slow hardener being relatively soft.

2) Will 635 epoxy self-level? I am looking for something I can also pour in a thin layer over the steel onto which I can mount my rails without a lot of scraping. I called USC and they recommended their Kleer Kote. I probably wasn't clear enough and it was only a quick call while I was driving, but it sounded like they thought I was looking to pour it onto a table or something and get a thick build with a glass-like finish, whereas I would actually be pouring it into a walled-in compartment and am not particularly concerned about a transluscent or satin finish.

So yeah, what have been your results with the various hardeners, and will 635 epoxy self-level?

Hi
I can give some answer on 1)
You may have great problems when mixing resin with short potlife. For example, once I mixed around 400 grams of epoxy with potlife roughly 30 minutes (some general purpose resin) and it generated so much heat that it started to smoke within 2-3 minutes (it was summer, that definitely didn't help ;) ), and it was unusable. More resin you mix, more heat will generate, faster cure.

Maybe get some samples and see what is best for you.