[Wswss] Help on stacking 1296 Yagis

[John]

Fellow UHFers,
Is there someone out there who can confirm a vertical stacking distance of
8.49 inches for a pair of M2 23CM22EZA.
This value I got using the DL6WU formula for 24 degree vertical beam width
1296 Yagi antennas and converting the metric result to inches. I simply want
to be certain of it before I start destroying aluminum.
Also, what length should the feed lines be from the 'T' connecting the feed
line to these antennas (wave length, cm or inches).  The antennas are out of
phase with each other as suggested by M2, their manufacturer.
Thanks in advance!  I'll be listening for you on 432.120 usb each Thursday
from 7 to 8 pm from DM13cm.
73,
John Kountz, WO1S