You should visit Waldo's site:www.wald-electronics.com
He's got a lot of preamp info. The Deluxe Reverb Reissue does a good job of sticking with the classic circuit. That circuit is very nearly the same as the Twin Reverb except instead of a midrange knob/pot, it's just a 6.8k fixed resistor.
But you can start by replacing the 100k plate resistors on the main preamp tubes with the Dale RN70 100k types. You can change the two tone-stack capacitors (.1uf and .047uF) for a pair of .022uF SBE Orange Drop 225p types. You can change the treble cap (250pf) to silver mica type. You can change the 22uf cathode bypass capacitors to Sprague 150d mil-spec tantalum types. And also there are other film cap's in the signal path that can be upgraded to the 225p Orange Drop types. Waldo's marked up schematic should help. There are more little places to tweak, but these are some good main places to make the amp more Jerry-like.