I'll just point out for all those still interested that in the example given by BOT (10 simultaneous events, each with 80% win probability, at odds -300), the solution limited to round-robins by 2 is actually Kelly-preferable to the the solution limited to singles.
Singles:
Stake Per: 9.99997%
Total Stake: 99.99969%
Utility: 5.07742%
By 2s:
Stake Per: 2.11675%
Total Stake: 95.25355%
Utility: 6.89867%
Although the complete Kelly solution, inclusive of all 1,023 singles and parlays, is obviously best:
All:
Total Stake: 26.84355%
Utility: 7.00211%
Singles:
Stake Per: 9.99997%
Total Stake: 99.99969%
Utility: 5.07742%
By 2s:
Stake Per: 2.11675%
Total Stake: 95.25355%
Utility: 6.89867%
Although the complete Kelly solution, inclusive of all 1,023 singles and parlays, is obviously best:
All:
Total Stake: 26.84355%
Utility: 7.00211%