The first question to be asked is what variation of the De Layens hive are you planning to build ?
The original is a very successful format, details of which can be pulled from Georges de Layens' book: Elevage-Des-Abeilles. There's an online .pdf copy (in French) at:
http://apiculture-populaire.com but as you will see from the following graphic, this format does require an extra-deep 16" frame, which will obviously need to be custom-made:
If you should decide to use this format, then simply stack your boxes, measure their internal height, then subtract roughly 0.5" - and make your frames that height. This measurement isn't critical as it's below the frame.
I've tried working with eleven 14" deep frames (see:
http://heretics-guide.atwebpages.com/beek15.htm), as opposed to De Layens' twenty 16" frames and, although the 14" does perform noticeably better than the British standard 9" deep frame, I couldn't entertain the idea of yet another size of frames in this apiary - so I've standardised on 9" and 12".
This is a shot of a Layens-style 'a grenier' (granary) format 20-frame Long Hive - designed to accommodate both 12" and 9" frames - with the two space-occupying boxes pushed together at one end.
I'm using this hive configuration for the first time to over-winter a medium-strength Carnie colony - can't comment further on this, other than to say I've seen substantial flying from the hive within the last 2 weeks, so it's a case of "so far, so good".
LJ