The beauty of an OA vape or trickle on a new swarm is that you only have to treat (disturb) them once, and very briefly. You know that there is no capped brood in the hive yet, so there are only phoretic mites to be killed, and for that you only need a one-off treatment.
Something like Apiguard is slow release, a longer term treatment to kill off the phoretic mites, and then stay in place for several weeks to kill off any mites that are in capped cells throughout a couple of brood cycles. Fine for an established colony, but it's a whole lot of unnecessary treatment for a swarm that doesn't need it.
Personally I'd recommend getting the kit to do OA vapes as your main treatment for varroa going forward - it's cheap (once you've got the kit) and easy. A basic pan vaporiser can be bought for about £20 (although you'd need a battery too), or a GasVap and torch is only about £40.
If you don't want to buy anything yet though, as JBM says, just use an OA trickle instead.