Hi Romy and thanks a lot for the always interesting topics and discussions going on...
I'm quite new to DPoLS and consider the approach of "obtaining sound in a room" more than "speakers positioning" - too often to WAF fullfillment and aesthetics, than soundwise - as a major achievement in audio at home.
I've been involved in the last few years in round Tractrix horns using, with several drivers: Altec 806, 288, JBL 2420, Coral 1", EV T350, Westrex 2080, RCA MI-9448 and several woofers by Altec 803, 416A and Westrex 2090, plus some Siemens (KL-405 and KL-306).
Pls forgive me for the following tale - will try to make it the shortest: quite recently, after purchasing during a quite long time-hiatus (almost a couple years), I finished owning (and using) three second-hand/pre-owned drivers pairs of Goto Unit drivers and horns, paying, IMO, a correct price-tag, BUT sure spending some energy, indeed.
The reason I'm writing? Not to say I consider myself as "arrived" to the peak, because I got Goto... no, definitely they're hyped piece of gears... the metal-finish on screw-in horn joint is awful, peeling off like the cheapest of cheap... industrially a below par workmanship, I'd say. If compared to MI-9448, they're ridiculously loosing on many parameters...
I got SG-17SA highs, SG-37FRP with S-400 horn mid-high and SG-555PS with S-150 (long, old style) horn mid-low... not the top of line they made years ago, but honest, old manufactured drivers bearing a quite "hated" name... and I entered in the blackest, deepest audio crisis ever... they sounded - compared to all the above mentioned drivers - a-musical, lean, unnatural...
DPoLS saved me... an idea, a concept gave to me strenght enough to "think", instead "re-selling" the difficult, unfriendly gears - and hinted me again toward humble experimenting... I had some carton jigs and cheap wooden stands made and... I began from where I was... classic quasi-horn 416A bass with horns on top, like 98 percent do... after, many, many attempts finished with a 3 upper ways wooden mounted array, 110° angled in front of, me, the listener and a cm 280 x 130 plus 100 x 130 "tuning-wings" baffle with Westrex 2090 woofers at center-stage.
This on the 5,30m "longest" wall... the wrong one;-)...
I'm still fiddling, and will have to for some times more, but it seems I found - at least - the position which give to me more music than I ever experienced in my room. Now, fine-tuning expects me.
I'm still moving mid-high and high as you did in yr. Macondo's... bacause I never seriously bothered with phase, I'm trying to learn using my ears and musical tastes... as travelling is not the place to reach, but the travel itself - I'm having pretty good time, in a sort of solitary conversation, ralationship with my room and gears, where a cartridge or a cable is as important as 1 inch movement or less... it's never too late.
... so, what about Goto? With their nasty snobbishness and elusiveness, they sure have the merit they allowed me, someway hinted and gave to me the ticket to a different, more mature?, deepest appreciation of music at home... which is not that bad. The second-hand lowered price-tages helped, too.
Would have obtained this promising results with what I already owned? Better for me, I'd say now... most important it's not considering the improving at an end, only "'cause I got Goto";-)))
... in fact, I'm also thinking to give a try to RCA's mid-low in S-150 60 inches long mid-low horns... their bakelite-cloth diaphragm is very, very musical and... well: let me play with my toys: it's my own adeventure! Is it or not (audio) a solitary affaire?!?! ;-)
Thanks again, Romy.
"Use your ears as your eyes" - Gertrude Stein