I edited my post, but in case you don't see it right away:
The network depends on coins being broken down into smaller pieces, but if your coins are in too many pieces then you'll never be able to stake all your coins in a single day. Check coin control (enable it in settings > options > display tab) in the send tab to see how your coins are broken down in the wallet, and their current age.
As for how many coins to send, depends on how many you have. Whatever you do send will immediately lose all their weight right now, so you'll stop staking as much, so that will be an important consideration. I'd suggest half, but check coin control and see try and find a reasonable balance from there.
Where is coin control?
got it: Check coin control (enable it in settings > options > display tab) in the send tab to see how your coins are broken down in the wallet, and their current age.
I see this now. So I understand I can chhose exactly which coins I'm sending to myself this way? And that chunks them for better staking?
Sorry for all the newb questions but this is new territory for me. I've never worked with a scrypt POS coin before.
If you do send coins to yourself, choose coins that just recently minted and would otherwise be immature anyways, that way you don't miss out on much minting time.
But if you keep staking in small portions now, each time you stake that's one less POW block as well.