The PE deck is more accurate in layout, and of course in scale thickness (tho it actually should be a tad thicker). Of course, it can be a problem to attach, and it does need shims.
AMP models are very soon to release a 300 piece set for the 1:72 Type II, with a metal deck. We've gotten around some of the Tupe VII problems by using wide and adjustable tabs, that not only eliminate shims, but offer big gluing surfaces. PDF flyer at AMP website, under Type II: http://amp.rokket.biz/amsets.shtml
Personally, I used the wood deck for my VIIC - I liked the painting surface and effect better, and think the thickness disappears because the slots are pretty dark. I used metal hatch covers for open hatches, and lined the edges with very thin plastic to reproduce the reinforcing wood used. But with the open hatches, them being right in scale, gives the illusion the rest of the deck is thin. Some pix of the deck and hatches here: http://www.rokket.biz/models/modelsweb/rokket/u557/finished.shtml
Something else I did was to use 2 thick styrene beams to hold the top of the hull together, as extra strength, so the deck would just drop in and not be structural.
Post some pix and keep isposted on your boat!
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