I think the operating license should be looked at long before you decide on an aircraft and how many airframes you want to operate. I assume the requirements in Spain are the same as the UK as far as personnel goes. You will need skilled personnel as post holders, Chief Pilot, Accountable Manger, Ops Manager, Engineering Manager and Quality manager. Even if the posts are shared, the overhead costs of salaries required for these people will amount to more than the purchase price of your aircraft over a loan period.
The maths in my head goes something like this. The 206 costs say $550 per hour to operate, it can operate 500 hours per year, thats $275,000, if you make 25% margin thats under $70,000 per anum to pay staff, phone bills, marketing, AOC charges and aircraft finance.
If you make more than 25% margin someone else would have already done it. And they have.
To me it just does not look practical.
However. If you want to test the market, have your company created, i.e. branding, website, promotional material etc and have a go, speak to the existing local operators and put their aircraft forward to your targetted client base with a small margin.
Phil