[TowerTalk] shunt feeding the sky

[Its from Onion]

Hello all,
I have just received a couple base insulators for R25 tower.  The kind that supports the
whole tower for shunt feeding.  
Thinking 125 feet tall for 1/4 wave on 160m.  

Questions;
1. Would a top section work, instead of that $1300.oo 'bottom' section?
2. How would you rate the capacity? 
3. Best way to shunt feed a WHOLE tower for multi-band?
4. Combining 2 towers for phased array. (future project.) 

Thanks in advance.

Lee
KE4VYN