check this out, one of the members here is doing the same thing on his Corsair. Looks pretty frsutrating to me but you might like it. You can get the checkerboard cowl decals on
squadron.com or
greatmodels.com if you decide against masking. Just do a search for 'P-47 decals'
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forgot to post the link to the topic
http://www.finescale.com/fsm/community/forum/topic.asp?page=1&TOPIC_ID=30227