Best mid top cab with Martin Audio S218+?

Stage at one end of the room has 2 spaces or 'cut outs' on the left and right hand sides for speakers to be floor stacked. Note - there's no chain hoists and I'd be very surprised if the budget would stretch to a small line array anyway. So, I think a pair of Martin Audio S218+ boxes would suit for some solid bass end - would a single S15+ be sufficient to cover mid top?

Or, how about 2 x S12+ boxes per side instead, using a single spacer pole with a double spigot?

Or, are there other makes/designs that would work better? Preferably UK made products.

Comments/suggestions welcome.

Thanks

Quite a high ceiling as it was a school hall originally, built in the 1880's I believe.

Owners have already bought some decent quality black drapes that are hung across the end wall facing the stage plus some more on the long side walls. There were issues with the hard, reflective surfaces affecting the sound not surprisingly and the drapes have made a big improvement.

What's the difference between Martin BSX and S218+ boxes?

Was the same driver used in both designs? Or, is the BSX more than a reflex design, uses a different (original) driver (B & C?) and is more efficient, plays lower etc..?

Are there any ASS MX600 boxes for sale anywhere?

To Levyte - what drivers are you using in your BSX copies and what amps are you driving them with please? And what amps for your ASS MX600's?

Cheers