Switching from retirement extension or ED visa to Type B?

Hi,

I have a friend that would like to move to Thailand asap and set up a company importing a few products from Europe.

I would like to help him with this and as part of the process I am trying to figure out which type of visa/extension would suit him best.

He is 52, British passport, no paperwork for education.

As with any business there needs to be a proof of concept stage so I am reluctant for him to open a company right off the bat as it may not work, then he is stuck with the company expense, 4 Thai staff etc to maintain his Type B visa if he wants to stay.

I can import a few products for him (I already have this setup in place with company and work permit) and test the market it that way.

However, as he wants to get over here asap I am trying to figure out what is the best visa for him to enter on with a view to switching to type B when we have the proof of concept on the products, which will take around 6 months.

Options seem to be come in on a Non O-A and get a retirement extension, or sign up with a Thai language school (which he would actually attend) and get the ED visa until confident in the business idea and ready to go for full company set up.

So - are there any known difficulties switching from retirement extension or ED visa to Type B? Can either be done without leaving the country?

Or any other suggestions for the best way to do this?

Many thanks in advance.