You can have as many number of units as you want. The minimum required is 1 and there is no maximum number. You can choose to go with 100,000 units at this time. However you can pick a bigger number if you anticipate growth in future and specially if you interested in selling the membership units to other interested parties.Good luck
units are similar to stocks in a corporation. if you plan on bringing in other members you can go with either units or percentages of ownership. it might be easier to go with percentages especially if you only have a few members.