From that picture looks like the pad is significantly forward, at least 1/2" of centered.
Look at the cylinders 7-8 "V" split behind the pad, vs. the 1-2 "V" ahead of it - see how much more V is showing @ 7-8?
Also looks like the side walls separating P from S slant down toward the rear.
The runner vanes are visible for cylinders 5&7 and 6&8, but underneath the roof on 1&3 and 2&4.

If this is accurate (more or less) any forward motion may help:
1. actual power
2. less chance of lean cylinder knock limiting the spark or jetting
3. save time & trouble trying out stagger (but will require tweaking any jetting already tried)
4. make plug comparos easier to read

This is not advice!! Proceed at your own risk. Good luck!
As my Dad used to say "Who dares, wins!".