I run my 25mm irc tyres at high pressures the trick i use tubeless tyres not normal tyres converted to tubeless. That is hit and miss and involves some faff.
Schwable have a tubeless version of the marathon supreme for wide. Two widths 35mm and 40mm.
Apologies if repost.. this blog post from (renowned vendor of wide tires) Compass showed up in my feed today, quite interesting:
https://janheine.wordpress.com/2017/05/29/the-trouble-with-road-tubeless/
tl;dr: tubeless no good at high pressure so go wide or go tubed.
I'm a bit skeptical, but then I run relatively low pressure anyway. Not too worried.