Ravestar, Im the chief motorcycle scrut for the DLRA , I can answer most of your questions
Q is the salt slippery ,compaired to a sealed road yes , and it depends if the salt is hard & dry or wet , a high powered bike will spin the rear tyre the whole distance from between 5% to 17% and greater , I have spun up the rear at 200+ fishtailing and shooting a rooster tail of salt
Q does the salt damage the paint work NO but its very corrosive and will cause severe damage if you dont clean up after racing , I strip ther bike down when I get home and clean everything , you can purchase some products (salt away ) or spray the bike with a solution of some sort of oil and thinner before racing , but you have to do a thourough clean after
Q The salt is usually very hard ,yes just like concrete with a thin layer (1cm) of very loose salt on top and yes you do need to pre drill holes to put in tent pegs
There are at least 4 members here that go each year I recon all members should come out at least once to have a look , Its almost racing time 3rd March
Cheers
Gary