I also expect the difference to be subtle, and possibly non-existent (to my ears). One of my first thoughts before even trying this was that I should do a control, just like you said, where I use NO forward spacing. But after starting to wrap my head around Gut's triangles explanation (that I posted a [crude] drawing of earlier in this thread) I really wanted to try it!
If I have time, I'll happily try to get a 4th hyper aligned with the LR mics. May not happen soon though.
I am also of the opinion that an XY pair in the center would increase the enjoyment for me. Do you place that pair forward as well?
In the samples below, I was fortunate to be close to the stage for pretty much all of them. I thought that allowed the center hyper to actually get great onstage sound from the actual amps and drums. Suuuper fun to play with in post. LOTS of ability to manipulate the mix etc. These may not be great representations of LCR recordings from the section, but it demonstrates some cool results with only 3 mics. Would love to one day replace that C4 hyper with a single mk41 cap > active cable.
https://samply.app/project/BHDbKcmpsQCtDSXnq5O3/Track 01 is at a brewery, but it's not as bad sounding as most breweries. I ran at a front row table, about 20-25 ft out, slightly ROC but pretty close to the sweet spot.
Track 02 is the same venue but different group (except keyboard player) but they did this super quiet but juicy opening track I wanted to share. Pretty much only keys are coming from the PA, so the CM4's are PAS getting great keyboard sound, while the hyper is pointed straight at the stage, getting drums, stand-up bass amp, and horns.
Track 03 is at a small stage in an enclosed back patio and is essentially indoors; but there's a tree literally in the sweet spot (pic below). It was an improv hosted by a popular drummer, so I decided to angle the hyper right at the drums (they were off to the left) as I wanted to feature him a bit in the mix.
Track 04 was outdoors, like 25-30 ft from the stage. bonobeats got a great onstage recording that's on the archive.
These were all recorded with a Zoom F6. The files are essentially raw except for normalization and dithering to 24bit (from 32fp). And mixing the amount of center mic of course. I did some mastered versions for the artists, but I also enjoy raw files, especially when discussing LCR technique.