I had one example that said that 3C Stayman showing 5/4 in the majors was comparable with a 2C stayman showing a 4/4, from my point of view these two calls would not be comparable calls

Hi Marion

I prefer to look at it this way:

If every possible hand which would make the substituted call would also have made the cancelled call then it is comparable

But one generally allows for minor differences with Law 23C available if it unexpectedly turns out the difference  was significant and assisted the offenders to get a better result.

For example a opening pass at partner's turn to call
Partner then opens 1 of something

Any call which is limited to below opening strength is comparable (such as single raise or 1NT (both being 6-9), and a jump raise or 2NT (both 10-12) would be close enough to be deemed comparable)
Every hand which would have made those calls would have passed as opener (not ALWAYS the case though; you might respond 1NT to 1S with S: xx    H: Kx   D: KQxxxx   C: xxx where that hand would have opened 2D as dealer not pass. In the highly unlikely event the knowledge that hand is excluded assists the side to get the a better result then Law 23C kicks in.
Any bid such as a new suit COULD be opening strength so is therefore NOT comparable

So in your first example if 1D shows 6+ points and 4+ diamonds
any call within that range of strength and distribution would be comparable
for example if 3D in that sequence would show  say 11+ points and 5+ diamonds then that is comparable

If a call shows two specified suits say S and D then the replacement call would also need to show those two suits
If a call shows two suits, but only one specified say S and another then a replacement call  showing S and D  is comparable
If a call shows ONE of two suits, (such as a multi opening showing (6 of) H or S) then a replacement call  showing (6 of) S  is comparable
(all of these subject to the strength being similar of course)

As for opening 1C (2+) out of turn:
If you actually had 5 clubs a 2C overcall (over 1 of something by the opponent) would be comparable, even (as is usual) if it has a slightly lower minimum strength than an opener
Apart from that there would be no comparable call available either responding to partner OR overcalling the opponents opener

There are some examples in "Commentary on the 2017 laws" in the directing tab on this website