Appending Site Name to Doctitle on inner pages

[earthy]

My site title is 'Event Photographer' and I'm considering appending the site name to doctile on inner pages, but want to confirm this is sensible and clarify a few things:

1. It's a succinct title describing what I do, therefore good to append. Agree?
2. Tagline is not included, right? If so, I wouldn't append as it'd be too long.
3. Better on right or left? Guessing right to prioritise other keywords on pages/posts.
4. Does this apply to ALL pages & posts?
4. Because of 70ish character recognition by SE, should I rewrite meta descriptions to be around 50 characters or less?

I want to be careful on this, especially after noticing a big % drop in traffic when I last tampered with SEO settings last week. (I changed homepage settings from site title to site description - now changed back).

Final question: My homepage settings are currently set to site title and I have nothing written in the Home Doctile section. Should I add something to the home doctile and what do I need to consider when doing so?

Thanks, thanks, thanks.