hmmm...yer not making it very easy at all, mate...if you're looking for entire replacements in 1/200 for purchase, I think you're going to end up empty handed, my friend...you may have to scratchbuild exactly what you're looking for, and I do know that Burkhardt Masch of BMK, Germany, does turn custom barrels in brass (and some mighty fine ones at that)...he may be willing to turn your barrels, shoot him an e-mail...as far as drawings of the Akizuki, I haven't seen any good ones, and IMHO, may not be accurate anyways (just think Hasegawa Nagato...

)...you may be better off looking for some good drydock photo's or the like to get an idea on the hull plates......let us know how you make out, mate, nice project!
Cheers,
~Gunny