For those who trade NYSE, or want to learn. THe only way to learn how to read one, is to just watch him. Watch him from 9:30-4:00. Don't stop. Watch him for at least a month or 3. When you think you understand him, move onto 3 or 4 more. After having watched specialists for almost 3 years now, I can basically group any specialist into about a half dozen categories or action types by just watching 5 mins of him, and looking back over the action from the last 2 days (the main ones are; stop blowers, whole and half blowers (i try and avoid trading the first 2), faders, gunners, gap and runners/ faders, futures traders, order flowers, sector followers (these are my faves to trade cause they lag the futs and the other stocks in their sector by 3-20 mins). Once I know that, I just play him like that action method. Anyone who has traded with me knows that even on those specialists that im the best on like abi and mo, I still only bat about 85-90% on. Sometimes specialists loose too (rarely). I have a notebook and every time I trade a listed stock, I write a few comments on that stock, and how it traded, and anything peculiar about it. That way, I can further classify that specialist into a personality type and figure him out better. I could repost my notes on all listed stocks, but honestly that would be similar to me just giving you free money. The only way to really learn unfortunately is to just watch.
As for watching inordinate size, that is much less important b/c of decimals. Basically, they'll just show you 100 shares each way, unless they want to make a point of showing you size. But you can basically see how many hidden orders and size of those orders by just watching how many 1c upticks there are, and by watching the t/s. Last week I traded almost 200k of nyse in a 4 day week, and hardly traded any nasd at all. The NYSE is far superior. I think market orders are the greatest thing, and it's a shame that otc market orders give you awful prints.
I really don't know how the new NYSE rules will affect the marketplace. I don't care about instant order entry at all. Let him fill me where he wants, and when he wants. Im not splitting pennies here. I will continue to use market orders as always (unless im fading a move and want specific order prints) Generally, the specialist has to fill you where he's quoting. There are some specialists that I have always gotten bad fills on, and now just refuse to play those names. He can move it a little, but that's it. Lately any move is accompanied by island orders to execute against anyway. I want to buy the dips, if it's running, Im probably looking to sell anyway, and not chase.
As for the open order book, I asume it leads to wider quotes and less activity by the specialist to step up and take the other side of an order just because large institutions won't show their true intentions on his order book. (im sorry this is kinda longwinded)