Agreed, but that statistics method is a bit more, what's the right word? "real world"?
Though doing as you describe is absolutely the best way to locate yourself in the right ballpark before you start fiddling.
Some sites let you donate to boost ratio, I rather like that as my outbound connection stinks. You'd think that sites that do this would be terrible, because nobody would seed, but it's actually the exact opposite, sites that let you bribe your ratio are always full of madmen connected straight into the uberpipe, who seed TB's not GB's. Those who can, do, those who can't, put their hands in their pockets to pay the webhosting for those who can. Just gives the lie to "torrenteers are miserable freeloaders"....I'd gladly pay the legitimate rights holders for the same service, but they're all still living in the 1940's it seems.
Some trackers do odd things too, like meter your download based on current upload on the specific torrent. Eg, you are seeding one torrent at 10KBps, and downloading another which is coming down at 40KBps, and has an outgoing of 10KBps, on some trackers if you stop the seeding torrent, freeing up outbound bandwidth, and allowing the downloading torrent to upload at 20KBps, your download rate on that torrent will ZOOM upwards to 80 or 100 or even to the saturation point of your connection (200-220-ish for a 2Mb connection). It's a Good Thing from the point of view that it strangles gits who have their outbound set to sod all, but it's a Bad Thing in that it encourages people to stop seeding completed torrents (at least temporarily). Some trackers even run a speed test on you, and throttle you if they detect a load of slack outbound bandwidth (they're few and far between though. I've seen torrents from demonoid do it, but I'm not sure if they were on Demonoid's own tracker or an external).
Finally, particularly with completely public sites....keep your eyes open, read the comments (ignore the 12 year olds from Sisterfuck Idaho who post endless "Ths Sux, doz nt werk" comments on everything from windows rips to text files), you'll have to use your own judgment when viri are reported in a torrent, read all the comments and decide for yourself if it's a false postive or not.....and of COURSE, keep your own defences up at full power when running/playing/unpacking anything from a public tracker site, you never know!