Few threads back someone asked about strapping Hrududu II on the Asshimar, got around to it now.
Works better than expected, all things considered. Obviously neither kit was ever designed with the other thing in mind but so far my only experience where the wing units actually kinda clamp onto the shoulders. Naturally that's easy with their size, but the entire installation is holding on only through that here, the booster pod is not attached to the backpack at all.
It is still a little awkward, I had to shift the hips forward to ensure the backpack can swing down far enough it doesn't get in the way. And the subarm is literally tacked on, but there's no way to make the drum frame fit in here. Good thing is that Asshimar IS supposed to have a drum frame in the back there, TR-3 was among other things a test machine for using that approach. The red circle denotes roughly where it should be as I understand, essentially a "spine" bearing the stress of the transformation's center axis. Makes sense to strap the Hrududu II there. That, or a second drum frame attached onto this one but it's not possible without modifying the kits quite a bit.