I don't see them reversing how they do the International sets with the November set. Our sets are typically the previous mini set and the following main set. That would have made it S3a Legendary Heartbeats and S4 Shocking Volt Tackle, yet it's very likely that S3a will be the basis for the 2020 mini set.
On the flip side, I think we'll see enough new cards from the 9 V Starter decks to make up the gap for our November set. If we look at the previous V Starter decks, each deck had a list of roughly 23 unique cards and each list had 6-8 *new* cards that have been added to our set's list. With that average, we can pretty safely assume that we're looking at 54-72 new cards from these decks, which wouldn't be crazy when compared with the size of the mini sets. Additionally, we'll see some of the secret rare cards from S4 added to that number (their full arts are counted normally in International sets, but are secret rares in Japan) as well as a few promos, so we'll probably have roughly 190 cards in the set.