I have the same experience with a 6126 platinum as underachiever. 390 scandi short, and a 450 aerohead. Your casting stroke will probably have to change to accommodate the longer head. I have only casted the aerohead on this rod once, so take this with a grain of salt, but the aerohead seemed to dampen the rod feel during casting for me. I'm not sure if it was caused by me (probably) poorly executing the longer stroke required, if 450 grains is just a little heavy for the rod, if it was line stretch, or if this is a common occurrence when casting longer lines. It just didn't give me the same feel that the 390 scandi short does. I'll have to put more time in with it. Please don't think that I'm beating up on the aerohead, I'm not. It casted just fine once I adjusted to it, which happened with just a few casts. Very quickly I was casting it without paying any attention to the extra length. Whether you're looking for less stripping, or more distance, this line is it. An easy transition from short heads.
Also, my understanding is that the aerohead isn't designed for polyleaders, just mono leaders. I may be wrong about that too though