It varies by coin, but in the case of Sync, I would recommend one large block via coin control, and leave it open. Sync has a very short maturity period, and the POS minting is going down by half every thirty days until it reaches 1%. Right now you want as big a shot at that minting as you can get. I'm recombining every time I stake. The few minutes I lose vs. The increased shot at staking early in the maturity phase is worth it with a six hour maturity.

Coins with a longer period, I pursue a different strategy, and when Sync gets down to 1% I'll probably be doing it with Sync as well. Break your blocks over the period of a week so that you are getting some stakes every day.

PoS coins have become my main focus, so I'm studying how they work with several coins, and there really is no "best" strategy for all. Each has a different character, even with similar specifications. I'm planning on writing up a pretty comprehensive coin control guide, but I'm still seeing how it plays out between several coins before I commit that to the internet.