I have *no* idea how many hours I've spent on it... but part of the issue is that every time I go off-piste it's not just the time to make, a massive chunk is research & design. I've probably sunk 10-20x more hours into hunting down parts, specs or modelling & suspension design than the *actual* making of bits.
Take the front suspension for example. The "kit" is to add a bit more taper to the Granada/Cortina uprights and bolt it all up. Maybe 5h a side.
In comparison I've designed my own uprights, arms and then made them. No idea how many hours but I've probably spent more time researching hubs than I would have spent assembling the "kit" setup.
I get that at workyeah, easily done, the research side is often 10 hours at home and an hour in the workshop.