Curly, I haven't straightened in years. I get crazy shrinkage and I need to hold and blow dry to keep my hair from curling real tight to my head. My hair when wet is almost to the middle of my back and if I don't dry it right it will literally dry up to my ears. It's very frustrating. I wanted something oily so I could comb through and dry without tons of frizz.
Unless you're blow drying on full blast w/out a diffuser, such extreme shrinkage and the fact that your very long hair shrinks right up to your head when dry suggests your curl type is probably beyond 3b (more likely a 4). Though curl type (size) may not be as important as hair properties, it can make a real difference in the way you physically handle your hair, like what styles may be easiest to achieve or the kind of handling it can tolerate before it splits or breaks off. ... Or even how much moisture the hair tends to need (3s and 4s tend to be drier because it's harder for sebum to traverse the length of more convoluted hair strands). I think that's one of the reasons there are different forums for different hair types.
You may also consider you could be trying to get your hair to look like something that it isn't ... I say this only because your hair seems to want to shrink a lot and do something drastically different than what you want it to, despite all your efforts. Maybe someone has other ideas and can prove this theory wrong. If so, great! I'd like you to make peace w/your hair, via whatever info you can get