Correct vent for steam convector radiator?

I've been working on getting my old, one pipe steam system in better shape. Replaced some of the old failing vents on the cast iron radiators with Vent Right #1s. They seem to be doing the job well. However, the kitchen has a convector type radiator and the vent (Hoffman 4a) let's out a whole lot of steam. I've made sure that this radiator has a slight tilt to the valve, but that change didn't help. Perhaps the next step is to try a new vent? However, the specific vent currently installed, the Hoffman 4a, is stated to be a "main" vent that is rated for 10psi, whereas the other cast  radiator vents are 3psi and I believe that the boiler is even lower. Is the same Hoffman 4a the vent I need for that convector radiator? If not, what type do I need?