Stiff oversize main tubes, fork blades for chain stays- this one is built in the style I have used since the late '90's when I built a bunch of frames for a local junior development team. Some of the frames I built got as far as the worlds and a couple of riders got National championships on a frame like this so on the velodrome steel still has validity.
The UCI used to have a maximum angle allowed for top tube slope- this bike is right about there. I'm not sure if the rules are the same but I like to keep the frame within the boundries that the UCI sets up, even if they are at times arbitrary and constantly in flux.
I had one pair of these seat stays I was saving for just such a frame. It is nice to take a bunch of tubes from different manufacturers and blend them into a harmonious set. This frame should be plenty stiff.