I was looking for some replacement HV cups and found these on e-bay:
http://www.ebay.com/itm/Color-TV-Fly-Back-Transformer-FBT-Anode-Cap-New-12-Pcs-/320844929120?pt=LH_DefaultDomain_0&hash=item4ab3d91860#ht_1529wt_107112 pcs in a bag...for almost nothing...

Close up...

I saw on the pictures of the ad on e-bay that there was a cut wire in the cup. I thought this was just an "example". Turns out all of them have cut wires so it looks like these were actually cut from HVT's or maybe just out of TV's or something......

With some prying it wasn't that hard to remove the wire and clip.

After a wiggle or four the wire comes loose...........

The cups are pretty small. Here comparing to a more "regular" cup....

Size doesn't say that much though. The standard cups on a Wintron/Lexel HVT are about the same size and they work fine on 25" tubes.
All in all.....I will use the spring and put it in the big cup for this application. I had that larger cup from a dead HVT.
They look useable enough for me should I need in the future but it takes some DIY...