I often here that people recommend making the line separation very close on 1/2a handles and wonder if just using a larger bellcrank and different setting on the bellcrank and control horn might be used instead to allow a more consistant feel on the handle.

  the bellcrank is the last part of the equation..u can get the lines so close that u wont have enough control.
  i built a profile Nobler and put all the newest and greatest controls in it , i could not get it to where it was comfertble to fly .got the handle so close that i couldnt keep up with it .i finally bit the bullit and cut into the wing and moved the pushrod to the inside most hole .that made all the diff. .i could move the handle spacing back out and not over control it now it is fun to fly  .i think a 3 in spacing is a good start for 1/2 A

Getting the correct CG and control sensitivity are 90% of the battle. Once you have them tuned in you can begin to trim the rest of the plane for tip weight, leadout location and trim tab settings.

Control surface throw at full handle deflection should be about 20 deg. with the handle spacing about the same as the size of the bellcrank.Then, what I do, is fly the model with my handle immobilized against my chest. It should track exactly where the handle is aimed without oscillation. Also, be sure that the lines trail out exactly at right angle to the handle. Bias up or down will cause inside and outside maneuvers to be different. Adjust the CG foreward or back until the model is just smooth. Now you have a good base to work from.

Yes, it is that simple. For more sophisticated trim advice, search Brett Buck on trim.

The handle and the bellcrank are a team that needs to work together.

The bellcrank is the receiver.  It needs to receive enough input to move 45 degrees each way from center.  The size of the bellcrank will convert this 90 degrees of total travel to a  solution in inches of input.

Your own personal wrist technique is different from everybody else.  So you need to find a handle size that converts your degrees of wrist travel in inches of line travel equal to what the bellcrank needs. 

But if you use an oversize handle you will transmit too much travel and hang the plane on one line.  This is bad.