I would start with a basic "honest" analysis calculation, vitally, do them independently of each other as much as possible
Start with a realistic estimation of sales for the first year, cross checked to what that would mean per day / hour.
Then estimate every costs, for the first year including
Cost of product / materials (based on the volume of sales)
Staff, including NI, wages, payroll services, holidays, sickness
Premises, business rates
Banking, loan repayments
Insurance
Theft
Damaged, expired stock.
Your wages, even if minimal
Advertising / marketing
Legal fees
Register company etc.
Accountancy costs
percentage of equipment costs, and building alterations.
Delivery, petrol, parking
Anything else that will cost the business
Then see which number is bigger, but (as mentioned previously) bear in mind corporation tax.
You may also want to run the number for years 2-5.
I ran my own media / tech related business for 15 years, and it was exciting, hard work and profitable most of the time. I found having a monthly profit / loss analysis vital to understand, how it was doing and when to sell it and move on. It's way too easy to think if you're busy you must be making money...
Good luck, but be brutally honest in your calculations.