I'm doing something in between. I moved into a house with a two car garage last July, where I was living on a boat until then (i.e. without a workshop let alone a garage) and decided to immediately buy two dilapidated old cars to restore completely by myself. A 1972 Lancia Fulvia coupe and a 1968 Triumph. Two, because I expect to be in this house (and garage) for long enough (two years or a bit longer) and because I want to amortize all of the specialized tools and equipment a bit (welder, compressor, all the metalworking and bodywork stuff, paint booth fan and filters, and so on). I am about halfway on the Lancia - MAJOR rust repairs, including new floors and fenders, and structural metal sections, full bare metal repaint, really everything that you can imagine on a 50 year old car. The Spitfire will be similar. I don't intend to make any business out of this but, for sure, had I had the Lancia done professionally it would have cost me around $60K at least. Now it will be around $13-15K and this is my hobby - so I enjoy (almost) every hour of it. I will seriously consider restoring more of these Lancia's in the future, but the plan right now is to just do these two cars and then we'll see if we move back onto the boat and that will be that. I have 0 training or experience in restoration/body or paintwork, but it's not hard. In the past I have taught myself, with help from many on these forums, in the technical side of things - that's also not that difficult, if you are willing to learn and work precisely. I am an accountant, no technical or trade experience.
All this to say - maybe you can do this yourself in your shop - see how it goes, whether you like it. Beware that the parts prices from Mercedes and other suppliers are extremely high, compared to many alternative classic car makes. The Lancia parts are at around 25% of the Mercedes, I would say, and the Triumph's parts seem to be even lower.
Good luck with the decision, I don't think it's easy to just start a Pagoda restoration business unless you know just about everything about them, yourself.