16 ohm speaker for OTL amps

Hi all.
I am currently in the progress of restoring a pair of (good quality) DIY Futterman OTL's.

Being OTL's, speaker impedance obviously becomes critical, and I am considering building a pair of dedicated 16 ohm speakers for them as a side project. I will need adwise though, but first a couple of pre-requisite informations:
The speakers will be positioned in a living room with open access to two adjacent rooms with a combined footprint of around 750 sq.feet. One speaker will have to be placed in a corner but this haven't been a problem in the past, as there's plenty of room for the sound to escape into.
Sound level is fairly low, hardly ever above 90 dB.
Distance between listning position and speakers 10 to 12 feet, with the same between them.

So, what do you suggest, look for 16 ohm speakerchassis which predominantly exists in the PA industry and design a 3 way say 10"/6" with a 1" horn/bullet tweete?
Or build something with two units in series, like an isovent/isobaric solution in the bass, D'appolito for midrange and two tweeters, potentially with one facing rearwards?

Just throw in your suggestions.