Some say the 20lpi is not fine enough, but 30lpi is too fine, and 40lpi is like none at all. Para does 25lpi on the front strap of 1911's. I would try that first, and see if it is what would work best. Good luck.
"A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
Life Member NRA
Life Member NAHC
Former President of the ECPT (Eifel Combat Pistol Team)