Dear J, LF Group,

You wrote:
...I have an RF ammeter which shows almost no antenna base current from 100 
Watt transmitter output. To get the 2.85 Amps will require much more power. 
I guesstimated about 410 Watts...

Going from 100W to 410W will produce just over double the antenna current,
so unless "almost no antenna base current" is about 1.4A, the power increase
will not in itself achieve your goal. If we assume for a moment that the
resistive part of the impedance of your antenna is in the range 25ohms -
100ohms, and the antenna tuner is reasonably efficient, the antenna current
should be in the range of about 1A - 2A with 100W TX. Being a big antenna,
one would expect it to be towards the upper end of this range. 

So unless the antenna current you are seeing is 1A or over, it looks like
your antenna tuner is still not working properly. Most of the TX power is
being dissipated somewhere other than the antenna, probably in the tuner
components. A large increase in TX power will cause these components to get
a lot hotter, probably damaging them. So it is important to sort this
problem out before increasing the TX power.

Cheers, Jim Moritz
73 de M0BMU