1) Are there other people creating this product in other parts of the country?  Would there be an opportunity to determine how well their sales are doing? Or is this product unique to you?

2) What is the shelf life?  If you make too much - more than you can sell immediately - what is the likelihood that you can store some to sell over the next couple of months?  A longer shelf life would suggest to me to make a larger quantity, hoping to sell in future months.

3) What is your cost of production? What is your potential profit from this?  Let's say you produce 100 units, and selling 20 units will cover your cost of producing 100 units.  If that is the case, and you think you can sell at least 20 units, then I would be more likely to produce more, plan to sell at least 20 units, and hoping to sell much more. 

However, if you produce 100 units, and you need to sell 80 units to cover the cost of producing 100 units, then I would be more likely to producing only what I knew I had a market for. 

Here's a final thought: as a producer of a product, your goal would be to sell out.  That should maximize your profit potential.   Every unit that you don't sell comes out of your profit potential........  as a consumer, I like to walk into a store and see product on the shelf.  I don't want the producer to sell out.  I want to see inventory available for me to buy when I want to buy it.  Finding that balance is the key.

I hope this helps give you perspective.  

Good luck on your venture.