Okay, first of all, I want to get this out of the way; I definitely one hundred-percent ship these two! Now that that's out of the way... I can get back to the main point of determining their Dere types. I'll start with Kuroko since he's a bit more obvious.

Kuroko is quiet and has very little presence, so I immediately categorize him as a Kuudere, through and through. He doesn't seem to have any emotion, and proves this later on in the show by not really caring too much for his friends.. actually, at times he was a total asshole. So, basically, I think Kuroko is... maybe 99% Kuudere, with like 1% Dandere... maybe. And that's on a good day. Those odd days he decides to be the cutest uke ever. God, I love him.

So, now on to Kagami. Now, I find it no coincidence that Kagami shares the same name as probably the most famous Tsundere there is (Taiga Aisaka of Toradora), because I think Kagami is the cutest fucking Tsundere there is. He totally denies his love for Kuroko (even though we all know the truth). Kagami just wants his little Kuudere senpai to notice him, but Kuroko is too busy being MLG to notice that Kagami loves him! So Kagami is in denial the whole time and Kuroko still doesn't give a shit, yet why is it so adorable and shipable? I mean, can you not picture kagami blushing, turning his head to the side and yelling? It's great! So, anyways, on to the example...

~~~Example~~~

Kuroko: (Tries to throw the basket ball in the net and misses horribly) ...

Kagami: Kuroko, how do you expect to be a great basketball player if you can't even get the damn ball in the hoop? (Does some sick 360 no-scope mlg dunk basket ball in net without breaking a sweat)

Kuroko: ...

Kagami: Don't worry, I'll help you be great.

Kuroko: (Looks at him, kind of confused) ...? 

Kagami: Th-That doesn't mean I like you or anything, b-baka! (Blushes hard and turns his head to the side)

Kuroko: (Thinks: ...) ... (Thinks: wtf...)

~~~End of Example~~~

So, this is both my thoughts on Kagami and Kuroko, as well as the obvious; why do I ship them? Hope you enjoyed :3.