another question on "bike to bike" 2 way radios

[tri5ron]

I have recently purchased a pair of Midland closed face helmet, speaker/mic sets to install into my wifes and my helmets.
model number AVP-H2.

I am waiting for the Midland GMRS, 2-way radios,(model GXT900), to become available soon. I chose this particular model due to it has AA sized rechargeable/alkaline batteries, as opposed to AAA sized batteries. As well as it comes with a DC/12v plug to rechage with, as opposed to AC only.

I will be installing these radio's on both of our quads.

I am fully aware of the outrageous claims by the manufacturer, on the range capabilities,
and I have a basic understanding of how UHF radios work in reguards to "line of sight", and "obstructions" are concerned, and how that affects the range capabilities.

I have also seen an available GMRS, mobile mounted, repeater station, that can be used to increase the operating range of the bike mounted radios.

The repeater stations, have an external antenna, that I could mount on the top of my telescoping flagpole, that I have mounted to my camper.
this would put the repeater antenna about 26 or 27 feet high off of the ground.

I am wondering if anyone here has ever set up or used a system like this, and how much did it increase the range on your 2 way radios?
How much did it increase the range from bike to camp?
and did it also increase you effective range from bike to bike?

Thanks in advance,
Ron