I have a possible solution to this conundrum:
I believe an easier solution would be to make firing the weapon a two step sequence.
1.) With your targeting reticule on the target, pressing the button locks the convergence.
2.) Upon releasing the same button the weapon fires based on the convergence setting from #1.
This way once you have the distance for the convergence you can then draw off the target and advance the reticule for lead. it should be almost transparent during up close combat as you would simply click and release to fire.
While this really only affects ballistics and the PPCs , it could also prove an advantage to blind fire LRMS as well. If the LRM didn't have a lock you could set the range and then advance your desired lead to the projected point. Essentially letting the enemy walk into the path of the oncoming missile barrage. ie.. a 3050 version of an artillery barrage.
Edited by Bad Karma 308, 18 January 2013 - 08:54 AM.