Various D&D Games - Player Limits

Soon, we'll be starting a number of new campaigns.

I'll conclude WAR 2 and will be starting the Slave Lords.
Kenji will be starting the follow on to the Buffyverse (uh name for your new series?)
Ross says he's ready to continue with the Slave Ship games.
Ken indicated that he'll be ready to run adventures again starting in Oct/ Nov.

So, any comments on if we should:

For speed of play, limit the number of players that attend any specific session?
If so, do players who played in that series previously get priority or should it be first to RSVP?
If players who play less, are able to make a session should they be extended an opportunity to catch up in number of sessions, replacing a player that plays frequently?

Should the number of players for all sessions be "first six to RSVP" ?

In some series, the continuity of the adventuring team is more important than in other series.

Also, I take the strong position that Kenji and Ross, the most frequent DM's (other than myself) should receive priority over all other players in attending sessions.

Just thought I'd put this out there for discussion...

Haven't played that much in the last year, but has the number of players been a problem?

When I've seen slow play it's usually:
* Players not prepared for their turn
* Monsters level/defenses are too high (players need a 17 or higher to hit)
* Excessive number of monsters.
* Monsters that weaken and have incorporeal.
* Player tactics (not taking out one, then moving to the next)

All of Ken's point are valid issues for slowing gameplay.
Extra large parties don't necessarily mean slower gameplay.
But it does mean longer durations between turns.
Player may get bored or tired while waiting for there turn.
Myself, I like a party size of 4 or 5 player. I think the last adventure we had 8.

Limiting players or player priority is a tough issue to solve.