I found and sized my pictures. Removing the foot rest bolts was kind of an experiment with me, I wanted to see what worked on the really tough jobs. The pictures tell the story:
None of the following tools got the job done:
These tools did the job (Vice Grips not pictured)
Years ago the commercial asked the viewer to decide if the Dremel was a tool or a toy. I've considered the question carefully, and in my hands it is a tool (and sometimes a toy).
Edit: An added advantage of the Dremel in the case of the foot-rest screws, is that they uncover the bolt and allow you to really shoot the penetrant in.
Of course, once you have the power to apply torque to the screw, it is very tempting to over-reach. In one case I managed to twist the head off after applying penetrant several times (PB Blaster), cutting the bolt and applying Vice-Grips in an impatient manner, that is, without twisting back and forth to wiggle the bolt free, but just "hitting it hard" and thus breaking it off in an over-abundance of enthusiasm.
Perhaps if I had beat and soaked it more it would have finally broken loose, but as it was I decided to apply some heat with a propane torch. Just a few minutes on each bolt, just enough to thoroughly smoke the previously applied penetrant, let it cool, apply more penetrant, and carefully applying enough torque to break the bolt loose, then "wiggle it free" got the last few bolts out.
In my honest opinion, I don't think the flat blade Truss-Head screws (1x8/9) make as much sense as the Phillips Truss-Head versions (QL). At any rate, I replaced the flat blade type with stainless steel Phillips upon re-assembly. So the finished product may not look as correct as Kraig's (yes, I noticed, Kraig), but I'm OK with it. The use of anti-seize is a good one.