There was a previous discussion on Stone Scoring:
And Rengo was brought up.
Well, I have been studying some ancient 4-4 joseki in Wizardry from the Stone Chamber (1590) and I was hoping to get a game going, though the feature is not implemented.
The way to do this seems to be using Chinese rules, setting komi to 0, and working from there (2 less points per group for the 2 necessary eyes). No issues right? Or am I missing something.
I think you are missing Seki 
For Seki, there is no such simple calculation, you basically have to check how many stones can be placed if players fill it, and different seki have different numbers (one sided dame, “false eyes” usually count as they can be safelly filled, three group seki “no eyes vs eyes” have you subtract 1 for two groups but 0 for the other, etc). For seki it is best to just ask players to actually fill as many stones as possible, and then count the actual stones in the final position, no “shortcut” as for “normally alive groups” where you can just count area and subtract 2.
That’s right. Seki is always an issue in rules so I should have guessed. Thanks for the pointer!