On mine that doesn't work as I have the european boot shape. You have do do it with one knee in each corner to avoid flexing the GRP. Even more uncomfortable I suspect. The real pain is avoiding kicking the spoiler when you get in and out for spanners a hundred times.
Struck that pose many a time with my '84. I will say that usually whenever I had to tinker at that end of the engine compartment I took the engine cover off. Took all of about 2 minutes. Didn't help much, but helped a little.