[Bob Steele]

My short perusal would indicate the same thing... counting mechanisms...
high count -counting mechanisms which of course could be used for low counts too...

If high counts are needed it could either be large numbers of objects on the field OR the anticipation of large numbers of objects all at ONE time...say perhaps in the end game.

High speed would also probably mean round... spherical...because other types of objects don't move through a scoring position quickly...

tennis balls - probably not... real easy to get up to speeds above 100 mph.
this provides a danger for refs, staff and spectators.. unless the speeds are controlled...

Same issue (in SPADES) for golf balls...

If I were guessing... wiffle balls...high initial speeds possible but they quickly slow down... limited flight...
these have been used in other competitions (FTC-VEX)
Cheap, easily obtainable...pretty visible if you get the yellow ones..

size...probably the softball sized ones...

Or perhaps a return to poof balls (hmmm in honor of the 254's CMP alliance win last year?... just kidding)

Those are excellent projectiles of a relatively smaller size... fairly easy to obtain... terminal velocity characteristics are pretty good....we have precedent for their use...

just my ideas... what say you?