There is another adjusting bolt, but you can't really see without removing the distributor. Once you know where it is, it can still be pretty tricky to get at without removing the distributor.
I always turn the crank around to top dead center on the #1 stroke before I pull the distributor.(remove the cap and check that the rotor is pointing at the #1 spark plug wire) This way I am alway very close to correct when putting it back in. Be aware that the rotor will turn counter clockwise (about a 1/4 turn) as you remove the distributor, so you'll need to install it starting in about the same location so the gears will mesh clockwise back to the correct position.
Good luck, it's not nearly as difficult the second time, or the third or fourth, 5, 6, 7
That's what happens when you start experimenting with distributor recurving. 