I was bored, so I did the math (for the calculations, I used kent etc.):
at 24k/seed: you need to buy 26 seeds to make up the meso lost. (1200 etc needed, 153,600 meso lost)
at 18k/seed: you need to buy 28 seeds to make up the meso lost. (1300 etc needed, 166,400 meso lost)
at 12k/seed: you need to buy 160 seeds to make up the meso lost. (7500 etc needed, 960,000 meso lost)
at 8k/seed: you need to buy 960 seeds to make up the meso lost. (30,000 etc needed, 3,840,000 meso lost)
or, if you happen to have 40k kent etc. lying around (equivalent to 5,120,000 meso) and donate all at once:
you need to buy 233 seeds to make up the meso lost. (5k/seed compared to 30k/seed)
At each step, I only compared the value of the seed to the previous step (i.e. you need 960 seeds at 8k/seed compared to 12k/seed, not 30k/seed)
at 24k/seed: you need to buy 26 seeds to make up the meso lost. (1200 etc needed, 153,600 meso lost)
at 18k/seed: you need to buy 28 seeds to make up the meso lost. (1300 etc needed, 166,400 meso lost)
at 12k/seed: you need to buy 160 seeds to make up the meso lost. (7500 etc needed, 960,000 meso lost)
at 8k/seed: you need to buy 960 seeds to make up the meso lost. (30,000 etc needed, 3,840,000 meso lost)
or, if you happen to have 40k kent etc. lying around (equivalent to 5,120,000 meso) and donate all at once:
you need to buy 233 seeds to make up the meso lost. (5k/seed compared to 30k/seed)
At each step, I only compared the value of the seed to the previous step (i.e. you need 960 seeds at 8k/seed compared to 12k/seed, not 30k/seed)