Originally Posted by Josh L

Yes, your right. The SCT pro only has a 6v 3amp BEC that will struggle with any HV servos.
I personally run a Futaba 9352HV servo, and the BEC could not deliver enough juice to keep it consistent until as you mentioned, I bypassed the ESC's BEC with the castle adjustable 10amp external BEC turned up to 7.2v.

However, I had already considered these factors before I posted a recommendation servo for Billthebutcher's consideration and cost requirements.
The Hitec HS-7955TG is not a HV specific servo, and can run reliably on as low as 4.8v or as high as a direct wired to a 7.4v 2S pack.
The specs don't post info past 6v, but if anyone has doubts on this, a call to Hitec customer support will confirm it's ability to run direct and unregulated to a 2S pack.

Here are the listed specs

Motor Type: Coreless
Bearing Type: Dual Ball Bearing
Speed: 0.19 / 0.15 sec @ 60 deg.
Torque: 250 / 333 oz.in (4.8v/6v) 18 / 24 kg.cm
Size: 1.57" x 0.78" x 1.45" 40.00 x 20.00 x 37.00mm
Weight: 2.29oz 65.00g

Give or take a half volt or a slight amp indifference from the SCT Pro's BEC ratings, this servo should produce a minimum of no less that 300oz-in of torque and never mush out or glitch, thus not needing an external BEC and saving him even more money initially.

If money wasn't an object, I would suggest the new XERUN XR8 plus ESC from hobbywing, as they now have an HV BEC that carries a switchable 6-7.2v with 15 amps. That should have plenty of current to manage any HV servo you could throw at it! But he won't really need that with the servo I recommended to do it's job very well.