yes i tryed to construct a pair trading system in excel and it ended up being very messy and time wasting, pt finder has been the best couple hundred dollars ive spent in my trading career as everyone can see in the journal. every professional trader i talk to uses some sort of specialist software to trade with, spreadsheets are for amateurs ive learnt.
the backtesting feature is pretty basic and gives the average correlation for the backtested period, number of trades, total PnL, avg PnL per trade, you can export the results into excel where there is a running PnL column of each pair and you can collate different pairs together to construct a portfolio equity chart, however they still have a way to go with the backtesting and its something ive suggested to them and I know others have in their pair trading forum aswell, they did get back to me and say the backtesting feature is being enhanced in version 3, due out later this year, im really looking forward to testing different money management strategies using the layers and possible scaled out exits according to the +/- stdev reading, also testing time based stops is something i suggested to them too.
But as with every trading system, is not about optimizing every last parameter, its about doing what is logical, practical and keeping a diversified portfolio of different pairs from different industries is as good as form of insurance as any other.