I like 4.0 for the front, and 4.5 for the rear trigger, on a big bore double rifle .450 cal and above. On a double rifle up to .400 cal I like 3.5 for the front, and 4.5 for the rear. If the rifle has a set trigger for the front (right barrel) then one must be careful how light that trigger is filed, for the un-set position! A set trigger that is too light,when unset, is likely to have a accidental discharge when pushed to the "SET" position. IMO, 3 pound front trigger, if it is a set trigger, may just be too light, so needs to be carefully done! Another word of CAUTION on set triggers, never fire the back trigger while the front trigger is in the set position, that is a guarinteed double discharge every time!

As someone above has already said, what ever weight you like is secondary to crispness, IMO!