Duleland break in time

The tin is not removable and bonded to the wire. No, it is not removed. 

I have used the KLEI and agree that they sound very natural after break-in. I struggled with 10 gauge wire and have a very hard time believing that a larger gauge will fit properly.

@grannyring Thanks for the recommendations. 

I own some of the Furez connectors and they do accommodate really big wire.  They are said to be pure copper and would work for the two 10 awg WE wires, but for some reason I like the sound of Furutech's copper better, at least when comparing spades between the two companies. 

The attractive thing about KLEI is that the conductor is supposed to be solid copper while most bananas are made from an alloy.  I am disappointed to hear they do not accommodate larger wire sizes.  I have linked their "brochure" below which indicates they will take large wire as quoted below from the brochure;

"Cable Conductor OD sizes up to 4mm (6awg)"

KLEI Brochure:
https://www.partsconnexion.com/media/pdfs/KLEI-83432.pdf

Assuming I am willing to live with "non-magnetic phosphor bronze" connectors these bananas linked below from Furutech look interesting and are supposed to accommodate a wire diameter of 5mm (which corresponds to somewhere between about 4-5 awg.  They allow a set screw connection, same as the FP-201 spades that I like to use.  The only reason I have not tried the Furutech bananas before is that I typically use pure copper connectors.
https://www.partsconnexion.com/FTECH-71115.html

@twoleftears Partsconnexion's ad says they are made from "Gold-Plated Copper" but without specifics it is not clear whether this is actual copper or an alloy containing copper.  I could not find out any more on their website but the items in their line-up appear to be of a high quality.

Interestingly, I looked up several of the other banana connectors listed and found a wide range of conductivity based on the metal used.  Bananas typically use an alloy of copper to improve ductility and durability over that of pure copper.  KLEI is an exception since they use pure copper plated with silver.  Below are some others and the associated conductivity relative to the International Annealed Copper Standard (IACS);

-Furez Tensioned Split Tube Banana Plug, C14500 Tellurium Copper - 93% IACS 
-Mundorf BFA Beryllium Copper Banana Plug - 60-63% IACS
- ConneX Connector Banana Plug, Brass - 28% IACS
- Furutech FP-200B(G) Banana Connector, Phosphor Bronze - (? see below)% IACS
(Phosphor Bronze is typically rated from about 15-20% IACS but apparently there is an "E" version ( 1.25% Phos. Grade E) that is rated up to 50% IACS.....I have no idea which Phosphor Bronze is used for the Furutech bananas)

I already own some of the Furez bananas so will use them if I need bananas.