Me encuentro perfectamente, y espero encontrame así por mucho tiempo

[ROBINDESBOIS]

I feel just perfect and I hope to continue so for a long time
is so ok in this sentence, or is it better to say like that?

[Perikles]

I feel just perfect and I hope to continue so for a long timeThat sounds as though you feel that you have no human faults. That may be so, but it is rather arrogant. :D

If you are referring to physical well-being, then

I feel just fine, and I hope to continue so for a long time.

fine/great/OK etc.

[Beto]

I don't agree that it makes you sound as if you had no faults. I think it is fine, but if I were to change anything, I would say "as such" en vez de "so".

[Perikles]

I don't agree that it makes you sound as if you had no faults. I think it is fine, but if I were to change anything, I would say "as such" en vez de "so".The interpretation of "perfect" is subjective, so you are quite entitled to disagree.

BUT: "I feel just perfect and I hope to continue as such for a long time" - That is not English as I know it. The pronoun "such" must have an identifiable antecedent, and is wrong if it doesn't. In the above, "perfect" is an adjective, and can't be an antecedent.