hi
maybe this will help you with the formula.
For Backing with Amount to win:
Trigger Expression (A*100/(100 - match_b_book))/match_matching_number_back_price is equal or greater than M
For Backing with Amount to lose:
Trigger Expression (A*100/match_b_book)/match_matching_number_back_price is equal or greater than M
For Laying with Amount to win:
Trigger Expression (A*100/match_l_book)/match_matching_number_lay_price is equal or greater than M
For Laying with Amount to lose:
Trigger Expression (A*100/(100 - match_l_book))/match_matching_number_lay_price is equal or greater than M
Where A is the amount to win or lose respectively, and M is the minimum stake size in your currency units.
mcbee