I replayed the encounter game from yesterday.
I didn't change any of the setup; I decided that I'd adopt the more cautious approach of allowing reinforcements to stack up before deciding when to advance. Here's the game a few moves in. The Swedes (left) had got three infantry units on, and advanced to the hill. The Russians had started with cavalry in play, and had sent them around the flank to threaten the Swedes but not, at this stage, engage. The Russians already had most of their infantry on as well - they got lucky with reinforcement rolls - and their commander was ready to bring them forward.
I'm not aware of any errors I made this time. And it played out in well under an hour, although not having to teach the game to a twelve week old child helped.