Turbo Integra wastegate location

I am running an internally gated td05. I had my exhaust side polished on my turbo. Not sure if thats the cause... But i am having boost creep issues when i had none before. My car is tuned for 16 psi. But shortly after vtec my boost climbs to 20+ psi. I have to let off the gas to escape certain doom. I took out my boost controller and am running the stock 8 psi now. But still after vtec it still climbs to unsafe levels. My question is.. Do to the design of my custom turbo manifold the only "easy" location for an external wastegate is on one of the runners. NOT where they all meet that would be the optimum spot. Do you think only being able to limit the exhaust comimg off one cylinder will have enough effect to stop the boost creep? Sorry for the long thread.

get a bigger flapper valve for the waste gate and bore out the hole to match it. Its a common modification on internal WG'd turbo's....they always seem to be too small for the applications people use them

BTW thats usually a sign that the turbo is a bit too small for what you're trying to do with it