Localbitcoins Automated Price Comparison and Advertisement Price Setting

The concept is that using by several variables we can set my brokers' advertisement prices in an automated fashion - I wish to maintain as high a profit margin as possible by only competing against other traders who hold similar stocks of Bitcoin for sale. This will be achieved by utilising the Localbitcoins API and a few Bitcoin exchange API's: Bitstamp, Bitfinex, and Kraken. The variables are as follows: minimum_profit_margin - The lowest profit margin I am willing to go to. An example would be that if the average Bitcoin price across the Bitcoin exchanges was £4000 and I wanted a 3% profit margin then the advertisement price would never go lower than £4120. maximum_profit_margin - The highest profit margin I am willing to go to. trader_limit - The minimum GBP limit I want to compete against. An example would be if this variable was set to 10000 then we would only compare against other traders which have a minimum of 10000 GBP for sale. Any traders holding below this amount of GBP for sale will be disregarded in the price comparison. price_difference - Dictates how we price against the cheapest competitor trader. 0 = match price, -0.01 = undercut by 1p and +0.01 = overprice by 1p. I also wish to include slight randomness in the price setting due to having several of my own brokers selling at the same time and I do not want them to have the same price. I also have to be fair with who is the cheapest and for how long; to this effect once the price has been output by the bot then I wish 1 of my brokers to have that price, another to be 10p more expensive and so on. Who receives the cheapest price must be refreshed every x amount of minutes (to be decided).