[TowerTalk] 160m. Inverted L question

[RVZ]

Guys,

I've got a 160m. Inverted L with the vertical wire spaced 4' from a grounded steel tower at the base and 6' at the top.  The radial system isn't perfect but it's decent.  Based upon the Inv. L's poor performance, I believe I may have a lot of power being coupled to the tower and shorted to ground.  A couple questions:
1) I'd appreciate some guestimates on what percentage of input power may be getting shorted to ground?
2) Any guestimate on what percentage of power may be saved if the Vertical wire spacing is increased from 4' to 12" from the tower? 

Thanks & 73,
Dick- K9OM