Can the no-API-key request limit be increased to 1000 for a certain amount of time - maybe 1-2 weeks?
I think you should register a Key.
Quoting the Key documentation:
When should I use a key?
The No Key limit is meant for light experimentation and simple development work. The instant you need the higher limit, it is acceptable to register for a key.Your application does not need to be in a releasable - even an alpha - state.
I would also check this question: Is it appropriate to register for a “Dev” app key?