1. What colour Koolstop brake pads to use? I assume these are better than the Ultegras I have bee using (not that they are bad. just need replacing).
2. I have a new pair of Conti Grand Prix Four Season to put on (25c). Could I run these as tubeless?

Swiss stop are better pads. I have run Ksyriums tubeless with many tyres but not had much luck with conti road tyres, they are very porous in the sidewalls.

1. Depends if they’re exalith or not. If so then I think you need the special swisstop ones.

2. AFAIK conti don’t make a tubeless ready tyre. The pressures are much higher than MTB so going ghetto doesn’t really work as you need a much tighter bead.

I use Swiss Stop BXP on mine.
I’d never contemplate running non-tubeless road tyres on a road bike.

Wiggles own Lifeline – better than Swissstop and a fraction of the price. Actually very good pads inusenthem in alu and carbon flavors.

I run Ultegra pads fine. DO NOT RUN THE CONTIS TUBELESS. I blew a pair of GP 4 seasons off the rimm rather easily. This was in my dining room. The tyre beads aren’t suitable.

By contrast, Schwalbe tubeless ready tyres will go up with a track pump. Running some G One Speeds and very nice they are too.