Hi Terje, I hope i didn't offend you by questioning the mutation of your new IRN - that was not my intention, I assure you! To be honest, 2 years ago, I didn't even know what an Indian Ringneck was, let alone what colours/mutations they came in, lol
I have merely become so intrigued with the breed, that any bird of unknown or uncertain mutation/parentage becomes a personal challenge for myself to try and work out what the possibilities are
When I first started learning about the mutations of IRNs, I was completely bamboozled to start with - but with the help of some very patient and understanding people from this site, and lots of research, it suddenly all began to make more sense - yet I still have so much more to learn! I have to admit, when they start talking heterozygous and homozygous etc, I get a little lost in the woods on that one ( I THINK I understand the basics, but haven't had much time to study that side of things yet
) Anyway, you have come to the right place if it's IRNs and their mutations you want to learn about. This is a great forum.
And yes you are correct, 'whitehead-whitetail' and 'clearhead-cleartail' (CHCT) are the same thing - CHCT is just the term that covers both blue series birds (WHWT) and green series birds 'yellowhead-yellowtail' (YHYT).
Thanks for the pics of your new hub, and his/her father - he's a good-looking bird, and if he is split CHCT, then I wonder if the mother is also either CHCT or split CHCT? Looking at the pic of the dad, I can see a pale-fronted bird at the back of his cage (to the left) on a perch. I wonder if that's mum, or one of the chicks?
Either way, your bub looks gorgeous, although the lighting in the pic makes it hard for a novice like me to accurately guess the colour. I would think there's at least the violet in him/her, and possibly Dark(Cobalt)….? But perhaps some of the more experienced breeders could give you some input? I've not ever seen a cobalt in the flesh (or feather, so to speak
), only photo's - and we all know how one pic can differ from the next, depending on light conditions
Anyway, I'd love to see pics of both parents if it's possible when you pick up your new bub. I'm sure you are waiting with much anticipation
PS: I'm thinking the dad may be double factor violet - based on comparison with my (sf) violet hen - he seems that way in the pic at least! So I'd be interested to know what the mum is, and have a play around with the GenCalc. If dad is say, (df)Violetblue/CHCT, mum might be D Blue, and CHCT or split CHCT…???
Now I really AM confused! lol 
I'll make sure to take some photos of both parent birds when I pick him up.
