A shaky start

[basix]

As a means of introduction what drew me to this forum was my search for a keyboard that would be conducive to shaky hands.
I can no longer touchtype but am reduced more to pecking with my right hand while a few keys QWASZX etc. with my left had braced steady on the left side.
  What I was wondering (Because I often double-hit a key on the membrane keyboards) would a mechanical keyboard with a heavier actuation weight and longer distance help prevent the accidental double tapping. I did try Cherry MX blues once and it seemed to help but the keys still seemed a bit wobbly. Since I do a lot of pecking would 'greens' or 'blacks' improve matters. Also do some of the MKs have larger key caps than others? I've read 'no' but the appearance on some of the 60% and 40% seem to appear larger. Probably an optical illusion lol.

[rmendis]

One suggestion is to get a switch tester to try out different options to see what suits you best.

Something like this: https://novelkeys.xyz/collections/switch-testers/products/12-slot-switch-tester

[vegs]

You could start with MX Blacks and see how the weight is for you. If those are too light, you can always order some heavier springs and swap those in

[absyrd]

Switch testers are useless. You can't get the feel for typing.

Keys on a mech are taller, but you only need to adjust to the proper hand, wrist and elbow alignment; this is also better for your long-term health anyhow.

The blues probably seemed wobbly because the keycaps may have been **** and the plate might not have been the best. Overall build quality of each board is why we have the entry level go-to mechs.

[AJM]

I would say, what would help you, is a switch with high "hysteresis", which means when a switch actuates at a certain point, you have to release the key a certain distance, until it can actuate again.

Switch testers are nice to get a basic idea of the feel, but they don't help in this case, because the switches are not connected to anything, so you can't see, when you send a signal with the switch or how many.
I would rule out linear switches like red or black, because their actuation and reset points are very close together (= low hysteresis").
Clicky switches in the style of MX blues have indeed a higher hysteresis, which would explain your positive experience.
If you have access to old IBM keyboards (Model M and Model F): These might work as well.

Concerning size of the key: The spacing of the keys is pretty much standard. Depending on the shape of the keycaps, their top surface area isn't always the same, which might look like different sizes.
But there are some special manufacturers, who do make keyboards with bigger keys. For example: http://www.bigkeys.com

PS: I'm just wondering - maybe for such problems there's come kind of software/driver, that simply waits a certain amout of time after each keypress, before it accepts the next one. Shouldn't be too difficult and it wouldn't matter what keyboard you use.