Lot's of good ideas for different kinds of groups and tastings. Discuss the options with your inner core and then put it out there. You can adjust as time goes by. Combining dinner and wine tasting can be a huge undertaking and takes the focus off of the wine.
I would advise to keep it simple so that the administrator, you, doesn't burn out. Meet the same day of the month, no matter what. Decide on the theme and price point at the previous meeting before you start drinking or soon after. I think price point is important for some kinds of tastings, that way everyone contributes the same general value each month. If people want to bring a surprise, say a great $10 bottle, to a $30 - $40 themed event, then they should bring it as an extra bonus bottle.
I think tasting blind is the way to go and having good stems is important too. People can bring their own if need be. Even if your group is more of a social thing, discussing the wines brings variety of conversation and keeps up the interest in the group. To that end, at the end of the night, some groups like to vote on their top three wines.
I've found it helpful to keep the emails brief and few. (monthly announcement and reminder announcement) Keeping a list of who volunteered to bring the cheese and who volunteered their living room keeps the group organized and aware of their responsibilities. Include this list at the bottom of each email. A little maintenance keeps harmony in the long run.
Ten people max keeps everyone, more or less sorta, together at the same table as well as each receives a decent pour.