If you come to live in Spain you must have medical insurance which covers you 100%. Co-payment plans will not support an application to sign on the EU Citizen’s Register, i.e. to become resident. If you come to work and get an offer of a job then you will not need medical insurance.
When comparing insurance offers you need to bear that in mind.
It will also be easier if the policy is written in Spanish to save to having to get an official translation by a ‘ court appointment’ translator.
Of course of you come 'just to see if Spain is the place for you' that is not 'move here straight away’ then you can stay permanently for up to 3 months without having to register.