To answer your question about breeding shinies, I personally prefer to collect 5 boxes (150 eggs), take off the parents from the Daycare, hatch all the 150 eggs, and if there are no shinies within the 150 batch, I repeat the process.
But it's overall a matter of taste. It really depends on how you prefer to hatch your eggs. Some fill like 9-10 boxes (270-300 eggs), some just pick up five, hatch them and reset, some do just like you... Do it the way you want, honestly.
