looking to automate untweets

Im working on a tweet/untweet schedule for my 250+ slave accounts in the food and Bev niche. Im currently using FL to build up a foundation.

First off, the goal is the tweet/untweet a few tweets from simple master accounts- Is this a good way to start driving traffic to our e-commerce site?

Second, Is there a untweet tool out there than can handle a large number of slave accounts? I dont want the slave accounts to just be spammed with the same 50 tweet for all time so I figured we could tweet then untweet after about an hour and then the slave accounts would look cleaner and seem a touch more credible.

Any thought on our system, offers to help get the kink worked out, or solutions to our untweeting needs would be greatly apreciated.

why don't you post new stuff and add your own in the mix? Like 80% curated content and 20% your own? This way your accounts will always look useful.

I can do this but I still want to untweet, any ideas?