Any question answered...

Trial and error is great, until you fuck threads (costing you more money), terminally buckle a wheel (by attempting to true it), set up your gears and they don't work, tweak them and they get worse, tweak them again and they get worser, tweak them again and they don't work at all, then take them to a shop who sort them out and have a chuckle about how badly wrong you had it.... or setting up your own brakes when you have no idea what you're doing and having them fail on you when you need them the most....

really, it's great doing things yourself, but unless you have a vague idea what to do, you're putting yourself at danger.

then again, you can find instructional videos on youtube for just about anything, so maybe at least have a look there...

wheels are fine. brakes i can do easy. just gearing bit of a bother.