I am quite fond of TQWT cabinet designs as they get horn like speed but go deeper for a reasonable size. I will probably do a modified version of Troels Gravessen’s DTQWT (similar to Horning designs).It's an easy speaker. Just make sure the cabinets are super rigid.
I recently heard some Lockwood Tannoys sounding like coloured mush. Easy on the ear,. but ultimately just mush.
Don't get me wrong some Tannoys when built right sound great. Not these Lockwood's IMHO.
I recommend Paul at RFC for a cabinet design here in the UK. Or anywhere, really.