I obviously wasn't quite as clear as I thought I was.
Let's assume you have a higher ABV batch. It doesn't need to be super high, e.g., a projected 16% ABV is high is you're using RC-212, which maxes at 14%.
B#1 gets EC-1118. B#2 gets RC-212.
The expectation is that RC-212 will quit around 14%, and when the B#2 ferment stops, inoculate with a fresh EC-1118 starter and let the ferment complete.
One description for RC-212 reads:
Ideal for full bodied red wines. Emphasizes fruit and spice notes, accentuates character in red grapes.
B#2 will have gone 90% of the way through fermentation with RC-212. Other than eliminating the remaining sugar, the expectation is EC-1118 will have a minor effect, if any, on the resulting wine -- the characteristics emphasized by RC-212 will be predominant.
My expectation is driven by both research and practical experience: Last fall I used Renaissance Avante and Bravo in red grapes, and the wines are distinctly different.