I always use a darker color and heavier thread (d) for the overwrap, It dosent show through the silver underneith. if all you have is he A thread a second wrap helps coniderably. it usually is more pronounced after flexcoating. You should also start to put a third color adding checks to the guide wraps, they make it look alot better.
Like Bewindel07 says reserve silver for third addition,trim thread only.Silver ends up turning a lite gold after a year or so do to the natural yellowing finish it goes through(its unavoidable no matter what brand used,age and sun will do its job)as a trim threadyellowing is harder to detect . Dont be afraid to grind them feet down to a nice thin taper so they wont crack through. Tapered guide feet alsoflex more with the blank and will less likely work its way through the underwrap and into the blank. Many blank failuresocurr at this point.
Thanks for all the input I did use D thread to wrap the guides on, the silver does not show through think the lighting was making it look that way but from now on will not use the silver for underwraps Thanks.