First things first - you plants look in a lovely condition and it seems that first week of high temps, didn't set them back too much!
50/50 coco/perlite is a really nice airy mix, more watering/feeding but amazing root growth, which is a bonus!
On average I do a 70/30 coco perlite, not for any real reason, it is just what I do but also like to play around at time so I may try other ratios in the future.
A while back I switched from perlite to growstones GS2 (for aeration) made from recycled glass which is then powdered so fine it is softer than flour and then a foaming agent is used and it is then heated in a kiln on a moving conveyor belt.The blend rises as it bakes and bubbles of gas released during the backing process follow a torturous path as they escape, creating a network of pore cells in the material creating a rigid and highly porous foam with the desired physical properties.
Growstones claim their GS-2 (for aeration) holds 70% more air than perlite, so I took the plunge and I see good results.
I also run DTW (drain to waste) but I usually end up with about 20% run off.
When you said "Bum Wine" I though that was a seed breeder or company, do you mean generic heavy weight/strength autos?
Your photo line up sound awesome and obviously seeing as your using boutique seeds, they are one I haven't heard of before in the UK.
I will be interested in how they turn out, I recon it has to be about 6 years since I last grew a photo. - cheres Arty