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It’s very subjective what is a bodge and what is a solution, with photography. Nowadays you are sold a product that is especially designed and marketed to do what you can succeed one hundred other ways.
A prime, plus extension tubes (or even just the filter), may suffer from a loss of a stop of light but you may gain a faster, lighter, more versatile and cheaper solution. It’s a lot of cat skinning.
Edit: also, minimum focus distance of 16cm really isn’t very close at all for that focal length, it’s acceptable for watches, but as I envisage it you will still max out your focal range and be cropping. You won’t get the best of up-close shots of the parts inside the watch.
I didn't say you didn't. Was just indicating that I'd prefer to buy the right kit rather than bodge something.