jack102,
You need to sit down and do a lot hard thinking about a developing a business.
From the beginning to the envisioned end.
Seek help from reliable sources and educate yourself. Take some courses and attend seminars in your locality.
Just what is a full production facility including ALL that it is associated with it?
You invest money to make money. So what is the total investment and operating cost of the manufacturing facility
and cost per unit and how does that compare with the competition.
Seek professional's who know how to manufacture something.
They can provide you with ball park cost per unit and upfront costs to start production.
Now think about this hard, they would have the facility and expertise do the manufacturing.
They also must make a profit, so do you think that you can build and develop and run a facility
and make a better return on your investment than using them?
The above is small insight to the question "Would I be better off just designing the products and having them molded by someone else?"
If you really know what you want to do then the rest is easy!

RICH