Ok so I did the Dirty Reiver last year , it was wet. The previous few years it has been dry. That makes a difference. However, last year i used panaracer gravelking sk in 700x38c, they were absolutely fine except for a couple of hundred yards of very serious mud where they lacked a bit of grip. To deal with the tyres you reference that I have experience
Pirellli c. RC - I doubt they have sufficient grip, I used the Pirelli C. M as my wet day tyre, they are not slow and have excellent puncture protection, especially on the sidewall. I would consider the H if the conditions are dry as they have a good rep for speed in dry but lack grip if it is wet. Anecdotally the RC Is neither one thing nor the other, it lacks the grip of the m and the speed of the H. Personally i wouldn’t try it out on the Reiver, wrong place to find it doesn’t work. Again the the M are definitely up to the job regardless of the conditions but won’t be fastest if it is dry.
Schwalbe g one. - I had these on until a month before last years Reiver, I ditched them because the sidewalls kept ripping, not just puncture but rips that were not fixed by three dynaplugs and I had to replace, they are fast, nice tyres for road and light gravel, don’t get me wrong, they are also provided on many new gravel bikes, which probably explains why the first 30km of last years reiver was peppered with split sidewalls, it was carnage. I dont have an issue with this tyre for general use as above but I can’t stress enough do not fetch it to the Reiver
Vitoria terrano dry - this is what I am running for /reiver 2024, it’s what I have been running all year on one of my gravel bikes (the other being the Pirelli c. M) . Do get the anthracite sidewall not the tan (or black) as the anthracite not only has the lower rolling resistance but also has the best bead to bead puncture protection. Don’t be fooled by the Dry in the name. I have used this all winter, done gravel events where I have been up to my crossbar in water, it is also ridiculessly cheap from decathlon
Comti terra trail - can’t comment, not tried, it and pathfinder pros are on my to do list but hard to come off the Pirelli M and the Vitoria Dry
One other thing: recommend. Inserts, I run Cushcore on the bike with the Pirelli (that had the gravel kings and schwalbe previously) and Vitoria on the bike with the Vitoria and maxis ramblers previously