One thing I might suggest is that you pick up and/or reference another, more up-to-date kit when you tackle some of these more venerable offerings, such as Tamiya's Shiratsuyu (or Harusame, I forget which one you're working with). For example, the part you initially described--part No.12--is not simply cantilevered out from the superstructure...it was supported from below to one degree or another: see, assembly diagrams 9, 10 & 15 here:
Dan attached a Pit Road while there are offerings from Fujimi, one of which includes the modified reload arrangements apparently executed during mid- to late-war Shiratsuyu class vessels. Namely, the after torpedo reload sheds to starboard were removed, thus providing only 6 reloads, not 8...all in the interests of weight savings I imagine: see assembly diagram 10 here:
This is just info for you; the idea is to have fun, not aspire--at least not yet and certainly not I--to Dan's level of building. Like washing dishes or working in the yard, I find modeling relaxing and a means to put the world's troubles at length. After all, what more could I hope for while I'm building up an old Airfix TBM-3 in Uruguayan markings, with as many trimmings as my meager skills will allow ?