@imhififan - Thanks again!
Spade to Banana Adapters came in from Transparent.
The spades fit the adapters and I was able to push the rack back to the wall (makes a big difference in this small room!).
No more worries about the really heavy cables bending/breaking the posts. The only way to fit one tip of each spade prong was from the top requiring an unsightly array of supports to prevent the cable from leaning/sliding and damaging the posts.
Really cool that I didn't have to modify the MIT2 cable. Preserving it is probably a plus as well.
Appreciate everyone's tips and advice!