Can I cheat and not get caught?

I bought a nice Accuphase P-450 power amp recently and was surprised to find the speaker connectors accept only bare wire or VERY large spades. Since my speakers are Vandersteen 3As, I had HCM Audio make a set of double bi-wired cables to the tune of over $300 (I know, that's cheap in the big scheme of things) and was shocked when the 5/16
spades would not fit over the posts. I was finally able to force the spade(s) barely onto the post and tighten the connector enough to secure it, but I'm wondering if it would be better to insert one prong of each spade into the hole for bare speaker wire, then tighten the connector. Or should I try to widen the gap in each spade slightly/carefully to get a better conventional connection? 
Trying to widen the spades will probably result in a broken spade. Insert one prong into the binding post hole, it should be fine for now.

Does your amp accept banana plus? You can use an adapter, spade to banana.
Spade to Banana Speaker Cable Adapters - Gold Plated (thick 3u) - Audiophile Quality - 4pk

OR spade to pin adapter.

No, the amp won't accept bananas....that's the problem. I thought of the spade to banana adapter, but I'm running into the same problem. It's hard to find an adapter with a spade larger than 5/16". Thanks for your suggestions, lowrider57.
I do have access to a Dremel-tool, testpilot, so I'll try that and shave a bit off the inside surface of a spade and see how that works (I think that's where you were going).
Yes, use a dremel tool.  I have had to do this several times.  Just work slowly and carefully checking for fit periodically. If the spades are not very thick you can carefully widen with needle nose pliers being very careful.  Thin spades are easy and safe to widen this way.  The thick ones are much harder and not as flexible so the Dremel works best here. 
I did mine the old fashion way, used a rat tail file and was able to accomplish in short order with good control