Reply To: booking time modes – mix or switch ?

I would make different forms on different pages for each way to rent the car and a global page as navigation that leads to the different forms. The “way to rent the car” should be the resources and you can select hourly and daily billing. Also choosing much amount of hours/days.
Or you make the same but for each car. So each car in each way to reserve is one resource and you make a form for each way to reserve and exclude the other ways cars ids in the [resources] select. Hidden fields for date and time will help you to fix some informations to the form and try out the [units] tag to select the num of hours directly. With this you can simulate 2.) in some way.

It won’t be easy, but it should work in some way. Availibility check too.