battery going dead on Silverado 2500 HD

Ok Guys

I have a 2005 Silerado 2500HD that is my work truck. I have had the following equipment install since new. A inbed snowex salt spreader that is power from the trucks electrial system. A Boss Snowplow and a wheelen 90 watt 6 head strobe system.  I have had no problems with this battery till 2 months ago I had a compustar remote starter install, all of the sudden the battery starts going dead. I have done the following things. Had everything disconnected from the truck and the battery stays charged, so that tells me its not the truck. I started hooking everything backup one day at a time till I had a dead battery again, last thing I hooked back up was the plow. The truck is now at the plow dealer and he is lost, says the wiring is all good no bad relays. So I now need detailed instructions on how to start checking for the draw.

What is a acceptable draw at rest?

What type of meter should I have?

What is the direction to start from, what is the first thing you would check, what is the last thing?

Both batterys and starter and alt all check out ok. Im lost and I need this truck to be able to start, and its starting to get very old.

Thanks Mike

I've read many articles on battery testing but I like this one for the simplicity without skimping on the tech stuff http://www.mightyautoparts.com/pdf/articles/tt63.pdf

25 milliamps usually flies but cold can affect what is acceptable.

Thanks Mike