See, that's where I'm confused. Didn't he say the seat pressure for those springs is 150? Sounds like that 150 is at 1.900" installed height, not 1.950". Not sure it'd make any difference though, but you may want to double check.
I agree, there's some ambiguity to the spring specs and to what Jeff was saying. If I take a conservative view and say the seat pressure is 138# @ 1.950", is that a reason for concern? It's 12# or 8% lighter than Hughes' cam card specs.