The only things I would change about this are that I'd make the train so a bit on a flat section after the roll so that I could do the traditional holding brake, and I would make the immelman a tad lower. I think if you inclined the immelman and made it a tad lower you could take it at a faster speed and still keep the G's in check. You had a couple very fine pumps I couldn't fix myself either but that is all I can really complain about trackwork wise. Supports and G's were totally fine, and I like the general idea behind the concept. Showing this off with colored trains and maybe in a plain grass environment would have been better, but I get what you were going for here. Maybe two car trains would let you take that immelman a bit faster too. Assuming they dispatch at interval, the capacity on this would be pretty huge even with two car trains.