need a bit of diablo tuner help
 

ok so with the retarded gas prices i decided to take the 93 oct predator tune out of the car and put in a 91. unfortunately my tuner doesn't have a 91 tune so i adjusted the timing back 2 deg (to the left of where the 93 oct timing was) for both the 2k-4k and the 4k-7k. my question is did i do it correctly? it went in .5 increments so i adjusted till it said 2. i went to dyno day and got 240 hp with 277 torque. (stock motor other than cai and tune) everything seemed ok. i just wanted to make sure that i did everything ok and to also ask if it would be safe to run 89 oct with the 91 tune? gas is retarded expensive here in vancouver (91 oct is $1.50) so i wont be putting in 91 very often. lol