Peerblock is pretty pointless but then again if you care about security and privacy you probably would not be using torrents, to that end if you want to feel secure without actually being secure (as far as not getting a fun letter, I believe it does have some minor malware options these days, though that is still no different to just using your hosts file) and using up a tiny amount of resources in the effort then carry on. About the only way to come close to being secure with torrents is get a suitable VPN or seedbox, both of which you tend to have to pay for.
Optimal settings.... as long as you do not try to enough connections to crash the average home router (a surprisingly low number in my experience) and you can upload and download you are good. Whether you have other fun things like the trackerless stuff and magnet links and whatever else depends upon the trackers you want to use -- most of the time they are harmless and will only trouble you if you sneak on to a torrent from a private site, get banned and subsequently get an invite to said private site. About the only ones that cause trouble are some of the encrypted headers and older trackers/clients, should you run into that then go on a case by base basis or just find a better torrent to do the same file.
