What do you recommend to reproduce this force curve from a rubberdome G213 to a mech. switch:
https://www.rtings.com/keyboard/1-0/graph#6518/6685
I found a mech. switch that has a slightly similar force curve. It is the gateron-zealios-62g:
https://i.rtings.com/assets/products/MOkjQkks/gateron-zealios-62g/feel-10-graph-large.jpg
But the zealios has a higher tactile point at 60. I need the tactile point at 50 like the rubberdome variant. What can I do here? If a replace the spring in the zealios with 50g or 45g will that do the trick or do I need something else?
I've been down this road.
Sure, Zealio V2 and especially the Zilent V2 are kind of like a rubber-dome force curve, for sure.
But they are a bit much.
They are highly tactile, with a high tactile peak force, and then they just slam down [that's why Zilent is the better of the two]. A lighter spring won't fix the problem, because it will just accentuate the high tactility. Then there's the Holy Panda, but it's almost as crazy as Zealio V2. You can tone it down by lubing heavily with 3204 or 205g0. I've built some Holy Bobas [similar switch] using 68 G Progessive springs, and it's relatively gentle, but still kinda crazy.
So your best bet is U4 Boba. It's a really new switch that people outside of enthusiasts haven't heard much about yet from Youtube videos, but it's rapidly popular among people who build.
The U4 Boba is a silent switch that has the tactility kind of throughout. It feels like some variants of rubber-dome / EC keyboards, like the ABKO 45 G [Niz domes]. Not kidding. So it's one of the closest to rubber-dome feel among MX switches, and I'm not the only one saying this.
This U4 Boba switch has a lot of good qualities. The first one is, it's completely usable in stock form. You can buy the 62 G or 68 G Bobas from the store, put them right in a keyboard, and they work great. The second thing is, you can easily mod them or buy them in pieces. This means you can make them more gentle, if you prefer that. Bring the spring weight down to ~57G [Long TX springs], lightly lube the slide rails and stem, and bingo, it's an office rubber-dome in intensity.
Also, they are cheaper than other silent tactiles.
Finally, if you want a more regular non-silent top-heavy tactile, there are a few options. First are the Kailh Pro Purples, which I have mentioned here a lot. The reason is, they have a force curve of pretty high weight at the top, then it just becomes a straight linear! It's weighted at 70 G bottom-out, the tactile part is somewhat stronger than MX Brown. It's a lighter and more coherently tactile version of Halo True [which also tries to mimic a rubber-dome somewhat, but is kinda heavy].
Anyway, the Kailh Pro Purple is kinda an outdated design these days, but they are cheap, and really do 'top-load' the force like a rubber-dome.
Another 'classic' is Kailh BOX Brown. They have a pretty decent tactile barrier right at the top, then it just sort of buckles or crashes down. Like stepping from a sidewalk onto the street. They're also fairly inexpensive. They're not silent, but there's a new silent variant called BOX Silent Brown that has the same shape, but it's a little more tactile, almost as much as Zilent V2.
What you should probably do is get ahold of some of these affordable Kailh switches that mimic rubber-dome force profiles, the Pro Purple, BOX Brown, and BOX Silent Brown. There's Halo True as well, but it's a little pricer and not as good.*
You can order this stuff from AliExpress, and also Novelkeys when they restock. Like you could order 10 of each switch, for cheap. You can also alternatively order a Kailh switch tester from a place like KBDFans / KPRepublic / AliExpress or maybe a U.S. reseller. For your use case, a Kailh switch tester or some giant all-in-one could be useful if it contains the above switches.
As for the U4 Boba, do what you have to in order to at least get samples. Maybe ask around on MechMarket, someone might be getting rid of a few. Otherwise you'd have to order at least 70 at a time. Although some places have samplers - ask.
Getting them into a keyboard is a different story, but let's tackle that hurdle as it comes. First, you have to determine which switch you like. Buying the cheapest possible hotswap keyboard could help you in that regard [they are getting 'cheap' these days].
*There's a discounted version of Halo True on clearance sale right now at Novelkeys called Kailh Polia. Check out the webpage and the Specs Sheet, which gives the force profile. You could order 70 to mess around with, testing, and later take the stems out to make Holy Pandas or Holy Bobas.
