I think we’re talking about it in the other thread.
Generally, my experience is that light tactiles want the spring to be weak at the top.
The reason for this is that higher spring weight reduces tactility. With an already low-tactility, you want the spring to be weaker so that it takes more effort to clear the bump. Otherwise, you can ‘lose’ the bump somewhat in a top-heavy spring.
Further to this, it’s better to have the spring heavier at the bottom. This is for function purposes. The higher the bottom-out weight, the more cushion, and also a stronger return. Both of these things are excellent in light tactiles, IMHO. This means using a slightly progressive spring, which you can get from the shorter springs like 14mm TX.
You can also use actual Progressive springs like Spirit makes, but I find that they can be very light and ‘empty’ feeling at the low weights like 63.5 G P when used in the “Brown-like” switches. For example, they turn TTC Watermelon Milkshake into a very light Brown, ‘floaty’ in feel. As a result, I use nominally-Progressive springs in medium and heavy tactiles instead. They kind of tone them down, somehow.
Alphadecay has pointed out the existence of a 14.5mm spring, which may be highly-desirable for use in light-tactiles. I haven’t experienced it yet, but if it provides greater cushion and return-force at the same weight [say, 58 G for the Meteor Orange], then they could be very useful indeed: