think i found the ultimate stealth character

[Zylo_Drizzt]

I've been focusing on the alchemist a bit cause it speaks to me above and beyond any other of the classes having said that I've found the gnome sabituer archetype which some of the discoveries allow u to have hide in plane sight and invisibility leading up to the grand discovery with improved invisibility. First does that mean I will remain invisible for 20 hours a day. If I just have the invis one will the invis refresh itself at some point or would I have to take an action or once its used its done

[Lich Bard]

The improved invisibility and spider climb work with your mutagen, and since you still have the persistent mutagen, yes, both work for 20 hours. You'd still be vulnerable to invisibility purge though.

I don't understand the second question. This ability comes with the mutagen. You have to brew it, and it takes one hour. There is a discovery that lets you have a second mutagen prepared. So the action to renew it would be brew the mutagen, and drinking it.

If you are interested in stealth, have you considered shadowdancer? It's a prestige class that doesn't require any particular class features. With just skill ranks and feats an alchemist can qualify just as a barbarian. Sure, you wouldn't gain those alchemist things, but you get hide in plain sight at level 1. Also, have you read about the ninja?

[Zylo_Drizzt]

Yes I have seen both but this is the only one that lasts for improved invisibility adds to stealth involves an alchemist and with a terrain character trait I can get stealth as a class skill yes I could go n get hide in plane sight in more easy ways however I don't see anything to anywhere near the same level as that combination