Beaded Bracelet help

Good evening all,

Could I get some advise please on making beaded bracelets. Just want to get things right, so thought I'd ask.

I'll be using sterling 4mm beads. I have a beadsmith board with various sized round circles. If for example I want to make a 7" bracelet, do I have to add any additional beads for more movement on the wrist, so its not a snug 7", or do I just make what the board says 7" and that would be considered good enough.

Asking because I read on the internet about adding a finger gap etc.

Also, if attaching charms to a bracelet, do they need to be welded? Would 0.8mm wire be ok?

Are there any books that would explain this at all?

Thanks for your time and any advice would be helpful.