[Antennaware] Small Tribander or SteppIR 2-element?

[RLVZ at aol.com]

Hi Guys,
 
I had great results with a SteppIR 3-element up 60' when  the antenna 
worked as designed.  Unfortunately, the Controller was bad  upon arrival, and 
then an 80mph windstorm blew two fibreglass elements off the  antenna which 
then allowed water into a Stepper motor and it went  bad!
 
Perhaps I'm a glutton for punishment but I'm seriously  considering a 
2-element SteppIR at a temporary QTH in the Midwest as the  3-element SteppIR 
turning radius may not clear the trees.  Question: isn't  the short 6' boom on 
the 2-element SteppIR too short for good  results on 20-meters?  I am not 
familiar with using  modeling programs and don't have the time to learn so I'd 
appreciate your  thoughts on this.
 
A 3-element tribander will work at this temporary site as it  has about the 
same turning radius as a 2-element SteppIR... and a Tribander  like the 
Hy-Gains TH3 might perform as well or even better better on 20-m.  (on the 
portion of the band that it is tuned for) as it has a  little longer spacing 
between driven element and the reflector.  Of  course the Tribander would be 
alot cheaper too.
 
What's your thoughts on the efficiency of a 6' boom length for  a 2-element 
20-m. yagi?
 
Thanks for your thoughts!
 
73,
Dick- K9OM