The truth is that there is no way to guestimate how it will turn out if you cant take every trade, it may be better or worse. Rather than guessing I sudgest you create distributions of the results. Here's the basic way. Use a random number generator to select trades each bar until your equity fully utilised (using your chosen money management). Note the final profit then do it again, different random numbers will give you different trade sets. After you do this 100 times (or more) you can analyse the results. Sort from highest to lowest. The middle or median is what you can expect the system to make with the chosen money management. The fifth lowest result (in a set of 100) or the fifth percentile is the kind of low result you could expect once every twenty runs (remembering that past results may not indicate future returns). The more complex way is to write/buy a program to do this for you, and graph the results based on profit, draw down, sharpe ratio etc. Also over what length of time is your historic lookback period, 30 trades per year is not much, you'd want at least ten years data.