Why Cat Size Does Not Change a Groom
Size classes are a dog thing. Domestic cats span a much narrower range, and outside the genuine outliers the practical difference between a nine pound cat and a fourteen pound one is close to nothing: the same table, the same equipment, the same handling, the same appointment length. What changes a cat groom is the coat and the temperament, not the weight.
The one place weight does matter is indirect. A heavy cat cannot reach its own back, sides and base of tail to groom them, so the areas it stops reaching are exactly the ones that mat, and a cat that has managed its own coat for years can pelt within a season after putting on weight. That is a coat problem with a weight cause, and it is covered on the coat pages.