[v0.9.0] Day instead of Nights

I'd like to use the system to rent an item per day instead of per night. I understand how to handle the language changes, the challenge I am facing is that the system figures one night stay as two days and one night. So if a visitor reserves for December 10th they need to check in on December 10 and check out on December 11, which is two days and one night. I need to have the visitor select one day, say just December 10th. Where would be a good place to start if I wanted to make a modification (preferably one that won't be overwritten) to change this behavior?

I appreciate your help, I do understand that the change will be something that we can't save as an overwrite and some core changes will be necessary. We are going to catalog the changes so that we know how to handle the upgrades going forward. I'd love to see some future development for this with SolidRes because the component could be used for so many more things than just room rental.

Hello,
I would like to do something similar, and allow hourly booking (check in and check out on same date).
Could you please give more details about the changes that need to be done in reservation.php ?
Thanks and regards
Max