Well, they could also do the latter themselves, in fact, it's easier to just split a couple of bitcoins into a dozen random outputs of different sizes and send them to the mixer, you can increase the number of deposits to 10,000 in a few hours and be done with it.

Also, if what you say is correct, then the mining campaign would reward people based on the number of deposits rather than the amount, so instead of someone sending a single deposit of 1 BTC, they could send 10*0.1 BTC, this will increase the number of deposits by 10 as opposed to just 1.

I believe both are equally important.

Say we have 4 Whirlwind pools.

Pool A has the following deposits:

1- 1 BTC from address 1111
2- 0.5 BTC from address 2222


a total of 1.5 BTC and 2 deposits, if I was to send 0.5 to mix it, the output with be 1 of 2, I either get 1 or 2.

Pool B has the following deposits:

1- 0.2 BTC from address 1111
2- 0.1 BTC from address 2222
3- 0.4 BTC from address 3333
4- 0.3 3BTC from address 4444

a total of 1 BTC and 4 deposits if I was to mix the same 0.5 BTC, the number of suspects isn't exactly 4 in this case since I'll need to get at least 2 deposits, this means 4/2, and the suspect addresses will still be only 2 despite having 4 deposits in the pool.

Pool C would outperform pool B if it has:

1- 0.5 BTC from address 1111
2- 1 BTC from address 2222
3- 0.7 BTC from address 3333

it's 1 of 3 now, despite having fewer deposits.

Pool D which outperforms them all would be something like this:

1- 0.6 BTC from address 1111
2- 1.4 BTC from address 2222
3- 0.7 BTC from address 3333
4- 3.2 3BTC from address 4444

Of course, I could be wrong, this is just based on my understanding of how the multi-sig pool works, I hope to get more clearance and corrections of the different pool examples I posted above.