Thanks! It's not lightweight -- the average script include I have right now is around 280k. I'm going to be able to reduce it in the next few months to around 150k, I believe. Once downloaded, the processing of it itself is not too intensive.
Thank you for taking a moment to respond; if I can get another question in, can you tell me a bit about how this scales with, say 10 or 40 images on a page as far as filesize goes? 150k in the context of modern web pages is not too far off from being realistic as an ad solution, depending on how many pictures it takes to reach the tipping point of page load time.
I have a test page that does 1000 images with 2-4 PLEENQs on each image, and performance is good with an 8-gig of ram mac mini and an iPhone 5 (my test platform for the mobile version).
I do about 10 million impressions a day, and the request to the server is a pretty consistent ~200ms, along with an async load that won't affect overall page load.