The downside to RNG is that you can get anything you want, so there's no need to trade with others anymore, except maybe for legendaries, events you missed, etc. But then again, if you get lazy like me, your reasons come back!
Uhhh. It probably took me a couple of hours to get the parameters and such, but that's actually pretty slow work. You can get that done in an hour if you know what you're doing or have help (like if you go to #tradecorner they'll help I'm sure). And to actually RNG my first Pokemon, it took a while cause I was doing it in the wild and not an egg, but I wanna say I got really good, reliable, and fast at RNGing after about a week. Congrats on finding your Lite btw!