I think as far as how long to categorize a model as new it should be 7 days as default. 7 days for her to get her feet dug in, figure out the sites interface, find herself a bit on there, and time for guys to find her as well. You could always add an option for the guys to change the setting to 2 weeks, a month or whatever if they took a break for instance and wanna see who they missed but 7 days seems fair to me for beginning.
As far as shows where girls can set it to be everyone Level X and above and the complaints here about how it would work and how it could not be fair for some to tip and not get to see a show the easiest way to fix that is just let the model choose on her own to add people. Someone tips and she can click their name and select add to show. Done. She can add anyone she wishes for tipping or for any other reason she chooses. Maybe it's to add a regular who tipped her offline, her bf, or someone who had tech issues the night before and missed one he tipped for, a prize from a spin wheel, etc.
You can still do the levels as it can breed competition for some and will give girls some idea of who spends and who spends a lot and maybe you can give bonuses to the higher levels like mentioned still. This just seems to solve any issues and be easier for both model and member.
If you are recording girls shows in DVR type for members I highly recommend making that available to models as well. It's only fair we have the option to get at our shows if members can too. Maybe we wanna take and make one in to a video for sale, or see ourselves as a member does to work on things like lighting or sound or angles or some such, or maybe something else but it would be nice to have one site that auto records us for us to have access to it too. SM takes and auto records and sells the vids for other sites to use as adverts, gives them to white labels to use, and even takes them and sells them on our page as if the model is doing it however the model can not even see it there and gets no money from the sales on them, control over them, or notification of such. Shady shady so please not only do not do crap like that but allow us to get our own recordings if they are there.