It is worth the investment in a couple of little click-on thermometers - about £10 I would guess. Balancing isn't all that difficult, but it does take a heck of a time because you have to allow time for the temperatures in the various parts of the system to change aftetr an adjustment has been made.
The other issue that it is not always clear which rads are closest to the boiler (in terms of length of pipework) and which are farthest away. You will just have to experiment. When you start, make a note of how many turns (measured in quarter turns) each lockshield takes to open it up completely - that way you can always return it to where it was if you get into a complete mess.
Do not be surprised if the rad closest to the boiler is only a tiny bit open (maybe only one quarter turn from being competely shut) - if you are getting the necessary temperature drop across the rad, enough energy is being pumped into it and being given out into the room.