I hard code pool ip addresses into the computer hosts files to cut down on DNS lookups. Not sure how much of your traffic they actually make up though and I've done this more to keep the router connections down than anything else.
DNS lookups are cached locally on each system by most OS, so this should produce very little data usage. My guess around data usage for DNS lookup would be under 100 megs per 10 gigs. your talking about asking to converting "
www.greenbtc.com" to "124.0.0.1" very liittle data involved
A real way to save data is to increase your share difficulty, the higher your difficulty the less shares you will produce and the less data you will transfer.
Say you systems are working on difficulty 1 shares and you switch to difficulty 4 shares, this would cut down your shares produced ~ 75% and save data.
You would just get paid more for the higher difficulty Shares.
but your pool has to support this and your miner software has to support this
Are you using a 4G,3G,Wimax based broadband modem?