I have the IPL speakers for mains and surround though in my case I’m 7.2 with no Atmos. I built the M1TML Ribbons for the main L&R and the AVC Pro Centre, if I were to do it all over again I thing I would build three AVC Pro Centres for the front sound stage as I don’t really use the mains for music despite them being UNBELIEVEABLE with music truly.
The DIYSGs are big American style speakers that are really best suit to huge American style rooms which we don’t have over here. I am sure they will go louder, I have no doubt in that but in all honesty I seldom push my Sony 1080 amp beyond half way with my IPLs and trust me they are plenty loud enough with zero distortion and a soundstage that is epic, the AVC Pro Centre is an amazing speaker, vocals project so well that you would not think they aren’t coming from the screen instead of below it and the impact is pretty special, especially once they are run in properly.
If you want to keep the price down the regular AVC 1-4 are good especially so for surround duties but if you can afford it I would recommend going for the AVC Pro Centre and maybe M3M Mk3 Ribbon for L&R, in fact if you could afford it I would have these for rear surround and the AVC 1 or 2 for Atmos.
Give Ian from IPL a ring, very approachable guy.