Bit-- you covered a lot of ground, I haven\'t got time to deal with all of it in depth.
1-- The reason we mark the races as \"S. pace\" is to alert the user that judgement was used to not use the final time (and if you want, to decide the figure is \"of suspect value\").
2-- Unless the pace is crazy slow (last year\'s BG, not this year\'s Risen Star or any other than a very few other extreme cases) the length relationships are not sigificantly altered-- if there is an alteration, it is slight. If that were not true, those races would not lend themselves to the analysis that we, Beyer and Time-Form use. We find the relationships in those races hold up very well in terms of the back figures the horses have run.
3-- In the example you used, Z Humor did run a better race than Pyro (which is to say that if they had run the race down a straightaway at level weights AND PERFORMED EXACTLY AS THEY DID, Z Humor would have finished ahead). However, you, the handicapper, are free to use your judgement to decide that since Pyro only got to run 1/8th of a mile he could have run much better. That\'s a COMPLETELY different thing than saying he DID run better. There are ways to deal with that issue (\"s. pace\", \"h?\"), but breaking out the relationships within a race is nuts-- it a) is based on an assumption that may or may not be true (that the horse could have run faster), b) is based on what, exactly, in terms of quantifying things, and c) means that to be consistent you would have to look at every race that way, and every horse.
4-- That\'s quite a definition of dominance. We do use figures to express how \"fast\" they ran, and interpret that in terms of effort.
5-- The Proud Spell/Z Humor question also applies to Proud Spell/Pyro.