your wastegate is probably fine. get one of the quick spool things, sinful6 here sells, or did sell them at one time. I have one on my car, with the stock wastegate i could never get over 15#, i had the adjustable rod tightend up farther than it was ever ment to go and still only 15#. with the quick spool thing, it spools up quicker (a little bit) and i can adjust it anywhere i want, i've had it at 22#, might be able to go higher, thats with a stock turbo though.
i know on one of the external gates, forgot which one it is, race gate or delta gate, they recomend using them to save the spring and internal parts.
the best part is how easy it is to adjust it, just turn it by hand and your done, no tools needed.
10# would be the minimum boost you could run, its a good place to have it unless you want to run a ton of bost later.