Appointments+ Plugin Questions

Dear Customer Service,

I bought your Appointment+ Plugin a few days ago and it looks great.
Unfortunately I have encountered some difficulties trying to adjust your plugin to the needs of my business.

As a consultant I would like to offer my services to customers via phone in time intervals of 10, 30, 45, 60 minutes. With the help of the "general setting" section I already managed to insert the intervals of 15, 30, 45, 60 minutes. Is there a way to add the time slot of 10 minutes as well or instead of the 15 minutes one?

Further I am uncertain what number, if any, to fill into the "Capacity" field.

For now there is only one service provider offering several different products like a, b, c, d, e.
How can I make sure that I am not double booked, while letting the customer see and choose from my different options?

Is there a way for me to simply block half a day, or a few hours in the booking calendar as a "one time occasion". For example: I have a doctors appointment and need 2 hours "off time".
I understand I can put in "fake" appointments manually, but then I would have to select a product(the longest takes only 60 minutes)and it would mass up my bookkeeping.

Thanks for your help,