I use my fingers.
Right hand - Hits 1 through 5 normal; 6-10 pointing left; 11-15 pointing down; 16-20 pointing right.
Left hand - Hits 21 through 25 normal; 26-30 pointing right; 31-35 pointing down; 36-40 pointing left.
If it goes beyond 40, start over on the right hand. Once the hits are known, we just pull that many pieces from the board. Each land piece has its own color poker chip (except ships, so many ship pieces), so armies get colorful and stand tall.