For any game with tech research in it, I like the tech being more likely to be discovered the more money you put into it. Instead of needing to roll a 6 on one die to discover the tech, you roll two dice and need to roll a 12, but for each previous roll, you get +1 to your current roll. So on the second roll you would succeed on an 11, on the third roll on a 10, etc. The average number of rolls needed to get the tech is about the same, but the variation is much lower. You’re much less likely to get it on your first attempt, but also much less likely to need 10+ attempts. To keep track of how many rolls you’ve made, place a die (or an airplane movement marker from Revised) on the tech chart where the control marker would go.