An Alternate Option

Your tokens distributed as you chose

Exchange 20 tokens now for 33 tokens if you reach round 3 and 33 if your reach round 4

As you chose

You distribute remaining tokens, plus 33 in rounds 3 and 4

Tokens converted to cash; you receive payment.

Cash value of unconverted tokens donated to charity (100%) or cash payment to you (50%)

Same, although neither you nor charity receive value of 33 tokens

Round 1: 100%; Round 2: 80%;
Round 3: 40%; Round 4: 20%