Attaching a docking port in orbit?

[Galane]

I want to try re-using the cores of my Duna* and Eve ships to go somewhere else. With the Eve core built on a ThunderMaximus tank with its matching 9 engine mount (that only has four Kerbodynes mounted) I'd like to connect the older Duna core to its bottom end. The Rockomax size will snuggle into the middle of those big engines just fine because the big mount can fit a Rockomax size engine to its center node.

Unfortunately I didn't have the foresight to pop a Clampotron on there before setting off on my "real" Eve mission.

I tried poking it with a claw mounted to an R1 RCS tank with a docking port on it, using Quantum Struts for bracing. That didn't go well, could not keep the two ships aligned once they got close.

I could be cheaty about it and use Hyperedit to replace that returned and parked in high Kerbin orbit part of the Eve ship, but attaching a port in orbit, and getting it dead center and rotationally aligned would be more fun. Need to be able to make a docking type approach to a part that's not a docking port.

*Which was in a retrograde orbit around Kerbin. Flew it out around the backside of Mun and back to Kerbin to get it going prograde.

[Tex_NL]

I added the Clamp-o-tron jr. to the list of KAS attachable parts. Works like a dream!

Only downside is using your jets during EVA. The mass of the clamp-o-tron totally unbalances the thrust.

[Galane]

I'd need to add the standard clampotron to KAS, store it in the large bin. Still the issue of getting it perfectly centered.