It's not long at all.. what's one minute?...knowing that the crysta is added to your account the second you paid.
That's how i did it a few weeks ago , i also did the same with ultimapay or whats it called.. no problems at all and both got me crysta without errors and within a minute.
Just be sure to check on paypal if you have enough money , because if not.. you still get an error.
You even can enable the auto-sub option if you make sure you have enough crysta on your account.