Thank you very much LoyceV !
Sorry for not answering before. I've been very busy and just logged back in. Ok, I understand, so for importing the private key, it's much better to use the WIF not compressed as in your example. I think everything's clear.
And as was said above, do not put it online if you think there could be any significant amount of bitcoin there. It is better to be safe than to lose a significant amount of value.