I've read it somewhere in the forum. I think people try these things in testnet to arrive to those conclusions.
And it's a fact that the shorter that constant the more forks/races will be. If there's orphan blocks with the current bitcoin protocol, it must (with the same size of the network) be more forks if that constant is smaller.
I don't know where it is, but I know that because I really wanted to know the reason for the 10 minutes.
And of course, reducing the 10 minutes does nothing for POS payments.
Just because someone posts something on a forum doesn't necessarily make it true.... (ironic eh
Firstly to understand how long a block takes to propagate you have to look at
A) The size of the block
B) The nodes capacity sending and receiving
C) The size of the network
In bitcoin (A) is an average of about 25KB right now. B) is quite unknown but if you consider the prevalence of broadband around the world and the minimum connection having at least a 16+KB/sec up and 32KB/sec down speed, which is a fairly conservative estimate. The size of the network, going by my rough estimations is around 3000-5000 nodes or so. Now when a miner sends out a winning block how long would it take given all these factors? Seconds.
If people on dialup need 5 minutes to receive a block then they shouldn't be running a full node in my opinion. They have alternatives, such as ewallets. Also with something like SolidCoin in the future which will have a method for so called "thin clients" to be able to confirm transactions without needing all blocks.
Should everyone be allowed to run a full node? Sure, if they can. Should the network cater to the lowest common denominator? In my opinion no. Like I said, people get stuck thinking about todays problems and not realizing where that path is actually taking them. You need a clear path to your destination if you want to succeed, so firstly you need to know where you want to go. Is your path 90 minute single confirmations?