Well done my friend, you´ve made the right decission when telling your client to better take a higher pole to get more light out of the lamps.
But sometimes like you mentioned, clients stick to their plans because of having them for years now from other produtction sites, and then the also learn something, moreover they have to spent some more of their money because of not taking in consideration what you recommend them to do.
Lets see it as a kind of win win situation -one has to do the same work twice and the other has to pay a bit more and therfore learned a lesson to take more serious the advice from their professionals 😉

I´m very happy to see you moving that fast from your first little jobs to now some bigger ones, I guess you´re also very happy with this evolution of your business, aren´t you ?

sunny greetings from the south of Spain 😎