The spring situation for Ergo Clears is somewhat confusing, because modern Ergo Clears often use Korean springs, and Koreans sometimes measure the spring-weight differently (actuation, instead of bottom-out).
For example, I've got some right now with 60 gr 1UpKeyBoards gold-plated springs, lightly bag-lubed with 3204.
But right now, I'm looking at Spirit springs, stainless, 63.5 gr. [Gotta choose between progressive, slow, or normal.]
I chose 63.5 because its close to Browns, and 62 gr Zealios, so it should be a familiar weight. [I prefer 60-67 gr. weight myself].
I'm assuming that 63.5 is the bottom-out weight.
If I understand the history of these switches, the 60 gr was considered the bare minimum to ensure proper reset of the switches. They could bind or whatever at 55, unless lubed. You can go as low as 50-55 with good lubing, apparently.
Since people were importing Korean switches, 62 gr became popular, and was considered reliable enough, so 63.5 moreso. So I think it has to do with the imported switches used, and minimum weight reliability.
If it were just about feel, I would probably use 65 or 67-8 gr. springs.
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If Zeal PC was still making V1 Zealios, I wouldn't even be making Ergo Clears. I would have just bought hundreds of V1 Zealios and Zilents for full-size boards, and I would have bought a JER-A06 to go along with it.
Sadly, that isn't an option. Ergo Clears are an enduring classic, though.
It's funny, it used to be if someone said "how do I get Ergo Clears" or "what are like Ergo Clears but better," people would just recc. you the Zeals. But now it's like, "just build Ergo Clears!"
I understand OUTEMU has been trying to emulate the Ergo Clears in its OUTEMU Sky 2.2 and OUTEMU Silent Forest lines. They are said to be scratchy and wobbly, and most people recommend lubing them to reduce the scratchiness.
As for Zeal, we can only hope he eventually turns that Blue Alps MX prototype into an Orange Alps MX tactile.