The only problem with foundationless is sometimes they like to build 90 degrees to the way we want them to build comb. Don't waste the money on foundation, I wish someone had notified me to save the money....want some?
You can get them to build mostly straight comb by always adding the new frames between two straight ones.
One of the beauties of foundationless is, that you can put your new frames right into the middle of the broodnest (one at a time!). That's because they don't represent a barrier for the queen. It's just as if a comb had broken off and the bees will try to fill the gap asap, giving you very fast comb building.
Only one caution: don't do this towards autumn, as you don't want unbred comb in the center of your hive, the bees might not cross it in winter, leading to isolation starvation.
Wiring:I use strong nylon fishing line, strung horizontally.
If you drill 4 holes into each sidebar, you can pull the line through, wrap it around a nail on one end, hammer in the nail, stretch the line and secure it with another nail at the other end.
You should be able to play it like a harp.
As a starter I wrap a narrow strip of foundation around the top line, but this might not always be necessary.
The bees will incorporate the fishing line in their comb, which makes the comb safe to handle and extract.
Fishing line won't conduct heat the same as wire, so the bees don't mind it so much. It's also nicer to handle.
Mine says 32.3 kg/65lb on the package.
If you get too much drone comb you can just use that for a full size honey super after the drones have hatched.
Best of luck with it!