I've been thinking about trying out vessery with two royal guards, but how hard would it be to fly him with two Phantoms?

Vessery + HLC

Sigma Squadron + SPA + FCS x2

It seems like it would be tricky to make those work together. Since the Sigmas attack long after Vessery, and can't target lock as an action, you won't get to trigger Vessery's ability on the first combat round or any round after you destroy the Phantoms' target. Still, it looks like a fun list to try. I'd keep all 3 ships at a distance from each other, and fly the Phantoms as hit-and-run ships, like Corran. Vessery can stay at range 3 and finish off wounded ships.

RGP's would probably be a much simpler option, though.

I think it could work.

I would personally drop the HLC to put a Weapon Engineer in each Phantom and give Veteran Instinct to Vessery so he can shoot sooner and move later.

With the Weapon Engineer, you open your target possibility a lot. Having a TL on two different ships, you become less predictable with who will be your target next turn. And it gives even more target to choose from for Vessery. Nobody is safe.

Having already two ship that fire with 4 attack dice, I don't think you really need the HLC. It will also relieve some pressure from him and you have more chance to keep your PS8 defender for the end game where they excel.

That's a team worth trying.

I like it. I might give that a shot then.