Pyrocatechin based developers (Pyrocat-HD and Diaxactol) tan and harden the emulsion as effectively as Pyrogallol developers ( PMK. ABC Pyro, Rollo Pyor, WD2D). All can be used for high temperature development up to about 80F or slightly higher.
If you already know the correct development time for a particular film at 68F, but want to develop at 75-80F instead, a general rule is to decrease develoment time by about 3-5% for every degree over 68F. The actual percentage increase varies with film, film/developer combinations, whether pre-soak is used, etc., but 3-5% should get you in the ballpark for most conditions.