Help with decking or not?

U show the end to end but the decks could also be sloped and or twisted
and it looks like 9.590 would be 0 deck ( unless your rods have been rebuilt- had the caps cut so shorter
closed chamber heads
you can try 9.6 and use the .028 gasket or if you have to go less and use a thicker gasket
remember some SBM cam with the piston above deck
you should be able to make it work
tight quench is better