Bike fit / correct riding position

Buying one of those is the best £5 I've spend as it allowed me to able to adjust the bicycle position with precise accurately;

Sure you can put your bike next to your old one and try and match the position, but it's never accurate enough that you could easily be 20-30mm too far forward etc.

Quickest and easiest solution (once you have a spirit level);

• Measure the distance from your BB to the nose of the saddle as well as the height.
  
• Measure the distance from saddle nose to the front of the stem clamp*.
  
  

See how it feel, ride around until you feel you want the bar closer or further away.

*some handlebar have a longer reach than other, compact drop have the shortest reach from clamp to brake hood, whether classic drop is much longer.