Go for it with street riding, that would make use of the bike you have. I keep thinking of swapping my stock frame and forks for more of a street setup.
Does it count if you are on a wall or on top of a building? If it does I can jump as high as you like. I was in an airplane the other day so technically I can jump around 30,000 feet
sounds a little like you are trying to hard. I used to get it on my DH bike when trying to do bigger jumps than I could. just relax and get really comfortable with the height you are at until it is so easy you almost don't have to try, then you can work higher.
I ride because I like to ride, I am not in it to be the best or win everything. Just being better than I am now and still enjoying it in 10 years would be good.
I used the gas hob on the cooker and a set of pliers last time. Let them heat up until the smoke cleared. Didn't take long. don't hold them to close to the flame or the glue will melt.
The best way to have the brake pads set is to have them toe inwards slightly at the front of the pad and as you brake and the forks twist the pads will press harder on the rim
If you have to clean them then.
clean the pads with alcohol wipes and then you could heat them up with a blowtorch. that will get out any oil etc.
clean the rotors with soapy water and then when dry and back on the bike give them a wipe down with alcohol wipes. you should wipe them with alcohol wipes each time you touch the rotor
sounds like you need to have a rest for a few days and let your back heal. If your back pain is coming while you are riding then look at your riding position. are you hunched over a lot? Because that will give you lots of aching in your back.
I used to run a Mad Phase 1.3.
These are the things I did to it.
1.Replaced the heavy stock forks for some light weight alloy forks.
2.Changed crankset I also set up as a single speed
3.I ran it with V brakes front and back. as long as you get them set up right they are great. I did try disc brakes for a while but they were rubbish. I also had a problem with the bottom bracket mount, it was welding on slightly twisted so had trouble with the drive train. I would get used to riding before you go grinding any rims too. As for upgrades, get some good wheels and a decent drive train.
If a spoke snaps it will change the shape of the rim enough to put excess pressure on the other spokes around it. Check they are all at the same tension. If your rim is true and straight then if they are all tightened to the same amount there should be no problem.