retumbo is a bit slower so it depends on what weight bullet your shooting, on a wag I would opt for H1000, then try retumbo both are in the hodgdon extreme powder line, meaning they are single based and not as temp sensitive, however be advised even the extreme powders will speed way up if you leave your ammo cook in the sun, or leave it on the dash in your truck when its warm, but not as bad as the double base powders
RR