any tricks or tips for a firmer, shorter shift?

A shorter handle will shorten the throws.

Make sure all the linkage is in good condition, loose sloppy linkage makes for a soggy shifter.

Some of the hurst shifters have a rubber insert where the chrome handle attaches the the shifter. This can cause sloppiness.

If it is a comp plus shifter you can replace bushings in the linkage.

If you are really creative you could try and move the holes on the transmission closer to the pivot point. This would require welding or brazing up the old holes and redrilling new ones. I haven't tried this but it should work.

But in the end, no matter what you doto it, it is not going to shifter like a modern internal rail shifter.