Obviously Estimated SC Score is not an exact science, given there is so many other statistical categories that go into producing a SC score, scaling and game situation factors, etc. FWIW from closely rewatching the game and specifically these players, gut feel is Walsh and Cripps scores are pretty well ballpark in my eyes, maybe Williams feels 10-15 overs, Heppell maybe 5 overs, and Cahill about right, he was quite impressive on the watch back and with a couple more effective kicks rather than turnovers would've pushed a 70 type number.
I was pretty strict on the ineffective kicks and also what constitutes a tackle in the stats sheet throughout. As I tried to judge everything as best I could based off my learnings over the years from my mate who works as a stats caller for CD.