Actually you can go any way you want like some veteran here said “everything is viable”. I think its Cathexis or Autentist.
High guard have a 60s CD which I think is quite crappy if you decided to deal damage other than your Blow Skills within the buff duration. For example: you think you don’t need it anymore after the 15s over the 30s duration, you can take off your shield to remove the buff and you will have to wait 45s to be able to use it again. With this, your Finestra will have an uptime of 90%. It’s decent. but will it crit/block enough? You decide.
On the other hand, PEL C1 is enough to tank actually. Just get the guard attribute and shield attribute and it will surely suffice.
Lastly, this is a personal suggestion. You can do what you want but nullifying Finestra’s negative evasion by Guardian’s attribute is a big waste I think. You better stack Gung Ho with Finestra and use Guardian (turn off Finestra by removing spear) when you need to evade attacks. Well you can still mix the two if you want to dodge and block at the same time which would reduce your damage output.
Disclaimer: About removing weapon to remove the buff, I’m not really sure and I can’t find the topic again but I’m sure its about a HOP + FEN discussion. Since you have access to the game(and Finestra), which I don’t, can you confirm this for me too?