Before you get ahead of yourselves... oops, too late!
You need to plan out the complete display and function set of this scoreboard. What sport(s) will it be used for? Will the team names or locations be fixed (i.e. "HOME" and "GUESTS"), shown on changeable cards or similar, or displayed electronically? How many digits can possibly be needed in each position? Will it need to display innings, frames, quarters, periods, ball possession, balls, strikes, outs, etc., etc.? Does it need a clock display (or more than one)? Will there be any need or desire for clock display(/s) to show sub-seconds, i.e. tenths or hundredths (decimal point)? Aside from an official scorekeeper to operate it in the expected fashion, what about changes dictated by referees/umpires/other game officials (stop, start, reset, preset, add, subtract)? What will you be using for a control interface?