New 360 & a couple of questions

FINALLY got my 360 a hair's breath away from starting it. I have 2 questions, though.

1) The car still has 87 octane gas in it from last year. The gas still smells ok but my comp ratio went from 7.8:1 to 9.2:1. Previous cranking pressure was 135 and new is 150. Will it run ok on the lower octane gas for start up and initial break in or should I figure out a way to get it out of the tank and put premium in it? I intend to drive it with premium.

2) Where to set the initial static timing? I was thinking 18*. What info do you need to posit a guess?