water bath tips?

looking for tips on how to give a water bath to my poor chinnie Tripp.



has anyone done it before? i know to blow dry him dry (on the cool, low setting). i'm worried i wont get him dry enough. how long should i expect to be blow drying him?



can i use johnsons' baby shampoo? ive used it on my guinea pigs before and know its gentle for them.



(tripp has his underside/bottom covered with urine stains and mats due to a combo of neurological problems and seizures. ive tried other options to clean his fur, with no real results.)