I think that someone can start a brand new tank and day 1 put coral in there and have it survive. And that's without cycling the tank. I know because I did it when I had my last tank crack and had to do an emergency transfer.
Now, provided that you've cycled the tank. There's no reason for your parameters to swing if you're not grosely over feeding or doing too large of water changes too often.
Its not too early to start, and I don't see a point in logging. Not to say it's not a good habit, but I don't see what could cause your alk or ca to swing. As long as you have an automatic water top off there's no reason for salinity changes either. Of course you should check, but you can get a feel after a few days how the trend is going to go.
The time when you really need to be on top of your parameters is when you add something new or change any equipment. Then you need to make sure nothing is going to swing.
I would recommend doing this in two phases. With phase 1 being buying some test pieces. Just a few cheaper pieces that would be nice long term if they survive. Then after a few months, buying a bunch of nicer sps that you really want to keep and filling your tank with those.
The reason I say this is because of the battle VS algae. Its very difficult to have a beautiful tank with sps when you're battling back algae constantly, and in my experience the all around best way to control algae is to have enough coral. There's a million things you can do to fight algae, but the only one with no side effect is adding more coral.
So if you buy a piece or two, measure your parameters, maybe learn how to dose for a few months then you'll be good to go.
