wreford-brown has a renown replacement mod for gwx that returns the reward for patrolling the grid
I'm not sure of the exact link for the standalone version but it is part of his SH3 commander mod pack which is worth using as a whole
http://www.subsim.com/radioroom/down...o=file&id=1873
I'm not 100% sure but setting a manual grid should only make the next patrol use the same again. After that i think it returns to the flotilla's set of random grids