Re: Wanting to stay with standard hives size.
I've not done it yet, but if I had to I'd be putting medium frames in the deep box either way. If converting from medium to deep it would be simple. You could even leave the medium frames in the deep. they'd just build three inches of comb on the bottom of the medium eventually I'm sure.
I run all mediums. Started that way. Yet next year toying with deep frames is on the todo list. They cost the same as mediums and hold three inches more comb so could run all deeps since I run narrow hives anyway.
If you have a deep box to convert to medium just put empty mediums in between the deeps until they get drawn. Chop off whatever excess they build on the bottom of the mediums. Then remove the other deeps.
Those are the only ways that make good sense to me unless you do a 'cutout' to convert from deep to medium.
Don't laugh it's paid for. -- Manure draws more flies than honey.