RID pool and user account creation

Hello,

I have a question about RID pool and user account creation.
Our system has two server farms each of which has two DCs (i.e. 4 DCs in total).
Two farms are a primary and a backup, and the RID master DC resides in the primary.
The entire system is under a single domain.


When the primary farm fails and the backup farm takes over,
we do not want to seize the RID master role at the backup farm,
because the primary might recover later depending on the cause of the failover.
Is it possible to avert the RID block depletion on backup farm's DCs
by setting a larger value to the 'RID Block Size' key (e.g. 5000) in advance?

In other words, is there anything that could potentially deplete
DCs' RIDs other than the account creation operations we perform
when our system enters the service (we will be creating no more than
several hundred user accounts).
We might create new user accounts while we are on the backup farm,
but the number of added users will not exceed 1000.
We will not create new computers and groups while on the backup farm, except perhaps a few.
Also we will be incorporating AD CS, Exchange, and Skype for Business
to our single domain system.

Regards,
Wanko