peter, after wrestling an F1 around a track for a few hours with your 'stay alive' competing with 'go fast', I would chug some bubbly from a used condom. *L* But it'd better be mine...;)
enginedr, pete..."Kiss Principal" protocol. If the ESS is centered over the lf driver, time alignment is Done, Rotation not necessary unless you absolutely have to have the base cabinet at a right angle to the wall. Since we're all familiar with 'toe in/out' of conventional speakers, that becomes the aesthetics of how you want the cabinets
to
look in the room...
Yeah, the ESS driver is a heavy little punk. Mine mount with 2 1/4" bolts vertically through the case. Those can go into either a T-nut or a threaded insert into a base plate of nice ply or even a plate of metal if one taps the holes in it..
BTW, been there, done that...I do this sort of thing daily, making 'things' go together...and making it look Nice....
Put a piece of rubber or Sorbothane between the driver and said plate. Although I've really not noticed any spurious vibration from the driver, even at 'full song', granted it could be an issue...
Mounting plate could be suspended above the base cabinet and the woofer with 4 threaded rods and some sleeves of metal tubing to set the height as desired.
A variation of the above could allow the ESS to be rotated and cinched down fairly easily. Since you're mating a dipole with an omni, and if you'd rather not rotate the base cabinet, it's doable without too much more fuss.
*L* I've gotten so used to doing the improbable with so little that mounting an ESS over an Ohm is Easy.
Of course, 'resale value' heads out the window, but...if you're 'doing a clone', that point goes moot...or *poof*. *L*
I could send a sketch of what I'm jabbering about, but I need to know that address...I do that sort of thing, too...;) And would be quite happy about doing so....*G*