wireguard multiple interfaces

The need is for site-to-site vpns (multiple client sites to one server
site), 3 vlans each.
From a management point of view it might be better to use 3 wireguard
interfaces on all of the routers (wg0, wg1, wg2). But I'm not sure if
that adds overhead, and if so how much.
Basically, is it better to use just one tunnel (wg0) or 3?

Thanks for any insights.

Chris