Hi Ben,
I operate my Broken Hill site (pp "s4") using a Telstra 7GB/mth connection.
I run planeplotter and flightradar24 uploader 24/7. I remote desktop for a look from time to time, plus the usual windows updates, planeplotter updates etc. I usually don't break over 5GB.
By the way...I'm using the NTC-6908T 3G modem...bulletproof
In regards to the choice of reciever. I insist on checking out the Mode-s Beast.
www.modesbeast.com ... Ultimate 1090Mhz receiver available, bar none. Reliable, predictable...and half the price of the closest competition.
Cheers...ƒil