Anytime
In my very early designs I've choosen a 10µF for the filtering of the input tube.
The idea behind was to obtain some more sag, when using high output PU's
But just a year or two later I've switched to 22µF in this spot, to get the amp still tighter and quicker in response.
In my early days first I've experimented with CTS pots, where the LOG/AUD taper was 20% to 25% resistance at half turn and I was very pleased with the sensitivity result.
Then I've placed a custom order at Piher/Portugal of 250 pcs. each value, but as I've got the pots it turned out, that their LOG just has been 10% to 12% resistance at half turn. Beginner's issues and my bad, that I haven't cleared this before placing my order.
In 1994 I've switched to Alpha pots in all my builds & rebuilds and this prob was solved since then.
Just a year later I've decided to use LIN tapers for the Middle & Treble controls.
As for the Presence control I've kept the LOG taper, although a REV LOG taper as already before with the Piher's.
In 1996 at a time, as the DINO circuit already was updated 5 times I've also changed the circuit of the power stage.
Since then the Presence control again is a LOG taper, but the Reactance control became a REV LOG taper.
Btw. no prob on my side, to disclose several more of my 'secrets', just feel free