Engine mount bolt sizing

[recapen]

I have my engine and prop back from inspection after getting hit by the hangar door (tornado, derecho, straight-line winds).

With only 168 hours on it - I'm going to re-use the rubber Lord mounts - but I am replacing the bolts, castle-nuts, and cotter pins...that brings me to my question:

When I originally installed the engine, I used the sizes specified by the plans (AN7-43 for the uppers and AN7-44 for the lowers). In order to get the hole in the AN-310 castle nut to line up, each set took an extra (meaning a total of two) AN960-7 washers 'under' each castle-nut. It was not possible to get a standard wrench around the top-left castle-nut to tighten it. Since each set required an extra 960-7 washer to get it to line up, can I use one size shorter bolt for the re-do and eliminate the extra washers all around - also allowing me to get a regular wrench on the top-left nut???
Ralph
RV6A N822AR @ N06