Here's a huge piece of advice from personal experience:
Make sure an independent third party has completely set up a ballot voting process prior to making your decision which will leave no doubts as to the outcome.
Send out a sample ballot in advance; have only one person for one ballot; have the ballot boxes at the event; then have third party people count the votes in private with PTA and PTO representatives present. Announce the results at the meeting, or at the subsequent voting meeting if you choose to hold two.
TRUST ME, I know from experience (which I'm not ready to discuss publicly), these points may seem stupid and assumptive to some, but you'd be surprised. I sure was.
It's rare (it's only happened twice, I think) that a PTO Todayer would be available to appear in person at a meeting like this, but you don't need us anyway. Tens of thousands of groups have gone PTO without PTO Today being there for a meeting. Glad to help you get a feel for the process and the pros and cons.
I would like to do this for our school this coming school year. Can you tell me who you contacted from PTOToday, please? Also, what type of questions y'all asked.
I would ask your two representatives on how they would recommend it. I am sure they've been through it before - no reason to recreate the wheel on this if you don't have to.
If they have no recommendations, I'd make it a formal meeting and go through your normal order of business and when the time comes, give them each an alloted time frame (10-15 minutes?) to state their case. Then, open it up to Q&A from the members and set a time frame for that (20 minutes?). At the end of 20 minutes you can decide it you want/need to extend it or if it's over.
I'd recommend getting some requently asked questions prepared and in your back pocket in case it's silent when the Q&A starts. Save them for last so you can use them in the akawrd silent times. Once a few questions get out, people will open up and it will run itself.
At the end, my recommendation is to not vote on either. Let people absorb it and talk about it and vote on it at the next meeting.
I am our PTA President and due to multiple requests we are having a PTA v. PTO Open Forum in April. We will have a representative from PTO Today present to answer PTO questions and (if they respond) our local PTA rep as well.
If any of you have attended or planned a similar meeting, I would greatly appreciate your views on how to set this up to keep things as civil as possible.