[VHFcontesting] Stacking Distance?

[AG2A]

I am in the process of cleaning my pair of 15 element KLM 2 meter beams. I 
was just thinking that I failed to measure the distance between them when I 
took them down (new tower,can't measure marks). Does anyone know the 
optimum distance for a pair of these antennas?  Oh yeah, while I have your 
attention is there a 432 or 435 simplex fm freq that is used for 
contesting?  I have a new duo band fm antenna but won't have anything else 
for the sept.contest.

					Tom - ag2a