I currently have 2 WBC hives; 1 active and 1 empty. I have the 2nd as I had a swarm last year and got the 2nd to house it but it didn't survive over the winter. Ideally, I would like 2 healthy active hives ...
It strikes me that you always need another hive to house the probable swarm one will have.
How do most deal with this?
Pardon me, if like Luminos I don't start where you expect.
You need some spare kit ready to deal with swarming behaviour from your eventual two colonies.
You need to plan the method of artificial swarm that you would use, and how you would reunite (noting that you have WBCs - which involve a little specific consideration).
That action is going to need spare kit (exactly what will depend on your chosen method).
And you need to consider that both your colonies might need attention at the same time! So you need something more (even a nuc box) as a temporary measure for dealing with hive number 2, while you sort out No 1.
Having two colonies (and some spare kit in addition) is a minimum sustainable apiary. You have on hand a full set of (bee) spares - eggs, brood, stores - should you find you need them!
OK. So, apart from needing more kit for where you want to be, where do you go from here? Unless you are desperate for a honey crop this year, I'd be thinking in terms of splitting your existing colony, and looking to overwinter two colonies. The split may be forced upon you if No 1 goes into swarm mode ... though you might still choose to recombine for a better chance of a honey crop.
You might then hope to acquire a late swarm (or make a late split, possibly using someone else's surplus queen) and try again to build it for the winter. All good experience.
In passing, I'd remark that single-brood WBC is very likely to go into swarm mode, because of having a smaller brood box than even the standard National. Brood and a half (or double brood, or the more involved change to 14x12 WBC) is advisable to avoid constant risk of swarming!
