Hi Greg,
Getting the bees to draw straight comb is 99% in making the hive level and providing good comb guides (they will sometimes do their own thing anyways, but most of the time this works well). If these are not attended to, you will not have straight comb.
I don't think wire or fishing line will have any impact on how straight they will make comb, and I believe that they will incorporate either into the comb just fine. We use all deeps, mostly foundationless, and don't wire at all.
deknow