So the plan is this. First 7 days are surely for the presale bidding, but it will close at a random number of days after that to stop last minute buying.
Coins will be distributed over the next 48 hours while we setup the genesis block, checkpoints, start the network going. During this period there are 2000 blocks with 0 reward. During this period of zero rewards we will release the reference client. That will give enough time for everyone to get setup, configure their pools and get started fairly.
if you've got a block time of 60 seconds (assuming) that's just a little over 1 day - so the pumpers and dumpers sit on the sidelines until you hit block 2,000 nd then jump in - a better idea is to have a high number of blocks required for maturity - let's say 2 to 3 days.
you get the same impact but do not penalize early miners with wasted mining efforts.
You are right and we thought about this quite a lot. The coin maturity is currently set at 500 blocks for this very reason and may increase it more (to 850). I sincerely believe that whatever the average bid price is set by the presale will have a serious effect on sell price. Miners are not just going to sell below market price if there has been a large presale setting the price higher. Also, there wont actually be that many coins available from mining in the beginning.
The zero reward blocks also solve another problem, because once we launch the network we will need at least the coin maturity before we can distribute the coins and further more, we want presale participants to be in control over their funds before any mining rewards kick in.
I'd make it at least one days worth of blocks. It's amazing how cheaply people will dump their coins. I typically am an early miner and put some of my coins up for about 500,000 sat for sale and then buy some of them back to get the price set then folks come in and sell for a tiny fraction of what I've set the sell wall at - it's amazing and it screws up everything moving forward.