David, I still have some of the original stuff in sealed foil packets (I keep thinking I should tell Bruce Barnbaum). I never used it as a push-processing developer - always as a contrast control developer. Bruce Barnbaum uses it in a split development process for contrast control.
XR-1 has long been my developer of choice for pictorial photography with Kodak Tech Pan.
To increase the contrast, you might try "kicking the pH" with some carbonate or hydroxide.