Long ago, I once assembled a set of Mk I hurricane bolters, which were metal. In addition to having a nice armour plate, they were also a pain in the @$$! With a Crusader sitting in the commission cue, there was only one option; Mk I-V.
I took the plastic bolters from the Redeemer kit, which were by far easier to glue together and would give a narrower profile to the sponsons.The pivot/rack was trimmed down alot, and fitted so it still attached to the plate.
The axle was positioned central to the guns with enough space to rotate freely.
There is one small piece that needs trimming on the back of one of the scanners so that it can still turn all the way.
The axle was cut just after the first bump to give the guns room.
The ammo feed under the gun also needs trimming so the support sits flush.
Until next round, be well.