Rent and Group functions

So, I've created some small shops and want to rent them out, and I'm getting lost in all of the options. I realize that there are many different ways to do this, but I'm wondering if some of you wouldn't mind sharing your thoughts about a couple of questions;

1. Is there a basic guideline for how much to charge in rent for a given allocation of prims?

2. It looks like I should create a group for the renters to join, but does this mean that I should deed my land to the group too?

3. How many people do I need to form a group - some of the documentation says 2 - other says 3?

I know that a lot of this depends too on where the shops are located and how busy the sim might be, but I'm just looking for general thoughts here.

Thanks in advance to any who might answer.

1. No. Do market research and charge what you think it's worth.

2. That depends on if the group needs powers that are dependent on the land, such as changing media.

3. I think you need two members that do not have owner status.

Thank you Cristalle -

I thought #1 might be the case, but the other two missed me.