Look the key to doing this sort of thing, is getting good quality gear for a start and installing it correctly.
BTW, just a note about IP Ratings, don't have a Chinese IP44 controller outside, they are as good as IP22 and will get water in them from the air, a waste of money, instead, use gear that has at least IP55 protection (encapsulated)
Over the last few Xmas's I've installed quite a number of elaborate lighting displays around town.
Mind you it is definitely a T&M thing, don't quote for it, you'll lose money, I've been there and done that.
Do the job once and do it properly, if you don't have to do any call-backs on the job, you've won for a start.
Let's face it, these days if you're not young, you're old - Red Green