Source suggestions for small spades

Look at this eBay item:

Gold Speaker Spade Connector 8 PCS For Speaker Wire DIY New

I have used these adapters with narrow width to fit old McIntosh and Fisher screws with dividers between screws

https://www.google.com/search?q=small+speaker+wire+adapters&sca_esv=60df094e8c3a7fc5&sxsrf=ACQVn08tkHqVmTEyQKE5TLWiYPoav4EZkA:1708010816482&source=univ&tbm=shop&tbo=u&biw=1280&bih=593&dpr=1.5#spd=624769687556198535

mine use set screws to fasten the wire to the adapter. choice of direction for wire entry

https://www.google.com/search?q=small+speaker+wire+adapters&sca_esv=60df094e8c3a7fc5&sxsrf=ACQVn08tkHqVmTEyQKE5TLWiYPoav4EZkA:1708010816482&source=univ&tbm=shop&tbo=u&biw=1280&bih=593&dpr=1.5#spd=8014896050538530367

Of course, looking at how those connectors are attached to the chassis, it does kind of make you want to make new one's with banana plugs, don't it? :D

I use connectors from Anticable...https://anticables.com/speaker-wires/2-channel

Minimalist designs, pure copper. They even have "vintage" pure copper spades which I believe to be what you are looking for.

The OP has a late 60’s Kenwood receiver with screw speaker terminals. He can’t use bananas on the amp end.

Based on your inability to properly measure the post, you need to find a friend with a set of calipers and maybe some DIY skills to share.  It isn't hard to learn but maybe you need a little help.

You need to fit the lug to the terminal.  A too-big lug gives a poor connection, works loose, and can twist and short.  

But lugs that are the right size for your wire.

I much prefer crimped and soldered to the ones with little screws.

There are cheap flimsy and low current lugs available in kits at Harbor Freight, Amazon, ebay and other places.  Avoid those.

Consider a BFA style banana which is much more foolproof and IMHO gives a better connection.

Jerry

If the amp uses plain screw terminals you want #6 spades.

The receiving ends vary as to what gauge of wire they will accept, but they are still plentiful and inexpensive.

DeKay

Just looked at the back of those.  Yes, Parts Express is decent but so is Amazon.  Honestly found the PE connectors for whatever reason never keep a crimp well enough.  I've thrown out many bags from them.  You'll want to match the diameter of your wire AND you definitely want to use an insulated spade.  The color on the insulation determines the size wire it is designed for.  The insulation will minimize the chances of your amp shorting when you move a cable or the receiver.

Absolutely recommend a ratcheting crimp tool specifically for insulated connectors.

You may also consider a ring terminal instead of a spade in this case, if the screws come all the way out. 

Parts Express