Present tense and conditional tense in a stated past tense

I have a question about using past and conditional tenses in a context that refers to something told in the past. I think I’ve seen both forms used in films/books, etc., but I'm not sure about it since it's really the only rule.

For example:

A.1. "You said if I can keep up you'll let me join in."

A.2. "You said if I could keep up you'd let me in join in."

The first version should indicate that "You" said to "I" in the past something that has the meaning (present) "if you can keep up I will let you join in", or better: something that when "You" told it had that meaning, so in the past was a first conditional.

The second version sounds better to me but maybe just because I'm not a native speaker.

The meaning sounds similar (and maybe it’s just the same in the end, just a different form of saying it) but maybe it reflects more a disappointment, like the one saying it understood that the possibility (join the group if he can keep up) is gone or it was a scam all along so it never effectively was.

The second example is this:

B.1. "He just told me that it's important and to give it to you when the time is right."

B.2. "He just told me that it's important and to give it to you when the time was right."

Both versions have the "told me that it is important". Like the first version of the previous example, here "He" told in the past that "it" is important, and it should still be in the present. For example, would it be a mistake to write "He said that it was important"? Or is it not a mistake but something that has a different meaning?

But my main question is about the difference preference "is" and "was".

Again, the second sounds better to me because in my language it would be something like that: a past tense followed by a conditional. Googling around I also found out that is the most used form for similar contexts.

The first version is like the previous example: someone said in the past something that at the time was in present tense. The "told me" it's like something that "bring us to the past" so it's not necessary to put "is" in the past too making it a "was". So whenever the time is right in the present, "it" can be given to "you"

The second version. I don't know, it just sounds better to me.

I don't know if I managed to explain my concerns. I hope a native speaker can enlighten me.