I have a Household Pet like that. I try to bathe her on Wednesday or Thursday before a show because it takes at least 24 hours for her to dry completely, and that's in an area with very low humidity.I think the grooming varies widely depending on breed and agree with @GoldyCat
's suggestion of checking out with other Siamese exhibitors. With RB it is important to retain the density of coat and brushing etc is avoided, hence my approach with not bathing but ensuring my cat's coat is clean and soft but also thick and dense. (I suspect if I did bath Mouse it would take about a week to dry out even using a hair drier despite his fur being short)!