Try 5-4-5-4 for sign, you will get back to full regen. Sign and other similar bars take less health so you can get a bit more hits in. Try the pattern I recommended. I have also asked other players and they said it's 5-4-5-5
If you wanted to, you can just unload on jobs to get extra credits and use them to regen. There's a 2% drop rate but I have found that Dutch Baking and a few others seem to drop credits more redily than others. I have already gotten over 40 credits in a few weeks, which is plenty to unload on a party and regen while not spending any real money. Yes, I know jobs can pay less than parties for some stats but if the goal is to fully regen while not spending money then that's how you do it and ignore hit patterns.