I have a play bike that has t5's pod filters, milled head and a timing plate at +4, I am running 350 mains and 27.5 pilots in it. I am also running tommey needles in the middle spot. I am at 900ft above sea level also.
Best thing you can do is do a plug chop. thats the only way you can be certain your jetting is right.
http://www.dfn.com/benkaren/plugchop.html