Cash as a tax free gift. Can it be in payments, or does it have to be one transaction? I know that it cannot exceed whatever the limits.?

The sum of payments over a tax year cannot exceed the limits.

the limit is annual, doesn't matter how it was given

Can be in chunks.

It can be in payments. However, the total of all the payments, when added together, can't be more than the limits.

What matters is the total for the year, not whether it's all at once or not. The limit is for not having to file a gift tax return and possibly pay an additional tax, gift tax, on it. You can't deduct the gift.