One more update to this thread. The kit's coming along but today I was doing some fit checking and I found that the fins on the pod were interfering with the rail for the B43s. Something's wrong, and after going over the references again I think I've figured it out.
This resource covers the options for pods and bombs under a B-58 in good detail: https://b-58.com/history_offensive.php
The first pod made for the B-58 was the MB-1C. Description from the above source:
The pod was 75 feet long with a diameter of about 5 feet. The pod was attached to the aircraft by three hooks. The pod had an equipment bay, a forward fuel tank, a bay for the thermonuclear weapon, an aft fuel tank, a tail cone and fins, plus an attachment pylon. The four fins were mounted at 45 degrees from the horizontal centerline and were slightly offset to give the pod a slow spin during free-fall.
So, one single full sized pod with four fins each 45 degrees from horizontal. The Italeri kit definitely gives you a MB-1C pod, and it's those fins that are giving me trouble.
Later, the TCP was developed:
The Two-Component Pod (or TCP) had the same overall profile as the older MB-1 and used the same attachment points. However, it was built in two separate sections. The TCP was actually two pods, an upper BLU 2/B-1 bomb pod and a lower BLU 2/B-2 fuel pod. The warhead unit could be retained while discarding the lower fuel pod.
The 35-foot long upper component contained two fuel tanks, separated by a warhead cavity. Maximum diameter was 3.5 feet. A pylon and three fins were fitted...
The lower component was also divided into two tanks separated by a common bulkhead. It was supported underneath the upper pod by one forward and one aft releaser. There were no fins, but a pivot strut was mounted on the aft end of the pod to facilitate proper separation from the aircraft during release.
The kit also gives you a BLU2/B-1 smaller inner pod, so if you want to depict a B-58 mid mission that has already dropped the outer pod, you can. However, it does NOT provide a BLU2/B-2 outer pod. Note that it has mostly the same shape as the MB-1C but critically, it does not have fins except for the one vertical strut.
This explains why there is some confusion as to whether the B-58 could carry external bombs and the pod or not. It could carry external bombs and a TCP, but not external bombs and a MB-1C.
Older versions of the instructions for this kit suggest using either one pod or the other pod or the external bombs, but that section seems to be omitted in the current version, hence my confusion.
I've spent so much time figuring out the right color and shape for the bombs so I don't want to give up on them, but nor do I want to forgo the shape of the full-size outer pod. So my plan is to take the provided MB-1C pod, remove the 4 fins, create the vertical strut by cutting down one of those fins to the proper shape, and then attach the fins intended for the BLU2/B-1 pod to where they would be on the full TCP assembly. It should be a relatively straightforward task, even given my fairly limited abilities.