The H-1 definitely has too much thrust right now, comparing to real numbers.

Exactly what the real numbers say seems to vary a bit, but this table in the Wikipedia page suggests that earlier models had 890 kN and later models 910 kN at sea level, or about 1010-1030 kN vacuum respectively. This gives a maximum scaled thrust of 422 kN. I see 709 in the config currently.

Fixed, thanks!