Depends on what format you are planning on building for. Fast gun is .794mms while big gun varies for Armor thickness. I am with fast gun so don’t know the big gun measurements.
From the MABG and NTXBG rules: Armor Thickness of Ship Maximum Balsa Thickness 0.00" to 6.99". 1/16" 7.00" to 11.9" 3/32" 12.0" and above 1/8" WWCC is slightly different: Armor Thickness of Ship Maximum Balsa Thickness 0.00" to 2.99". 1/16" 3.00" to 11.9" 3/32" 12.0" and above 1/8"