Are you talking about the Helix hot Spring here, or the one that came with it?
Does the Helix one fit without any modification to the spring? Also, does it not put to much pressure on the positive connector board like you mentioned trying to avoid?
I was talking about the cheap .59 large battery spring from madvapes being too big. It's not a hot spring and is not very maleable, even when using pliers to try and adjust it. It's not optimal for this mod.
The Helix spring works fine, is a hot spring and can be adjusted with just my fingers. The large bottom part of the spring is a bit smaller than the inside of the cap, so just uncoiling the bottom just a bit makes it fit nice and snug in the cap.
Now that my batteries have a more secure ground contact they seem to be lasting longer, but that could just be my imagination justifying the purchase of these springs.