Hi,
Race kings are good tyres – nice and quick. I have a pair of 29" Ralphs and they were also pretty good. Fast rolling and large volume too.
Do they do the race king in a protection 29er? The Schwalbe sidewalls don't last too long unless you go for the SnakeSkin versions which are excellent.
Freds are awesome – the lightest by miles and very. very fast. However, there is little grip and they are very thin. Excellent for Sherwood/Thetford/Catton/Eastnor when it is dry as there are no technical sections and no rocks. Other than that they are a bit deadly.
The Bonty tyres (29-0, 29-1) are very good value at £25 each or so compared to other brands, but are not available yet. Maybe the end of May.
Have you considered the Stans Crow? 450g or so, bald as a Fred but the carcass is a bit meatier. Pretty expensive though.
GB