Horizontal wires add strength. If you don't use them, the extract with
care and keep the comb warm.
You can get away without any foundation at all, if you want.
I experimented, and continue to do so, with waxed-wire frames. The
technique is to put two or three (3 is better) coat-hanger guage
wires horizontally in each frame and to coat them with bees'
wax. The bees will build comb hanging down from the strip of bees'
wax on the underside of the top-bar and from each of the wires.
As the combs grow downwards, they coalesce into a complete frame
of comb. The resulting combs are strong enough to run through both
tangential and radial extractors. The main problem is that you must
keep the hives exactly horizontal accross (along doesn't matter)
the frames so that the combs hang exactly vertically as the bees
build them. If the combs hang askew to the end bars, then the
comb isn't flat and you may get a mess. I do warn you, that bees,
as perverse as they are, may not follow your waxed-wire instructions.
But, it has worked for me, most of the time! I learned this trick from
a beekeeper near LaBufa, Chihuahua, Mexico.