This guide is somehow odd , seems to be written from someone that haven't played a paladin , anyway my point is not to flame , just giving away another point of view on the paladin specially on the solo / grind / istance tattics .
First i've always sticked whit shield and sword both for grinding or while running istance whit the combat mercenary talent active ( sword spec + resiliente life + bronze sinew ) .
As for grinding i'd never went after mob 1 by 1 , but just aoeing , we got so little damage anyway that we can afford to stack a good ammount of mob . Perfect Defence was always then started luring mob around once i've a good ammount on me i'll just build charge ,switching beetwen different mob aka 1 hit each , to 4/5 charges and then releasing wirlwind chop then again another 1/2 charge to finish off the mob who's still alive. Heal up rinse and repeat . This was the best proficient way of grinding i had during the CB way faster then killing mob 1 on 1 , and funnier tho .
Also for istance , for tanking a boss perfect defence always up for sure , then to just hold aggro Hot blloded Surge always up is enough while you build up charge for the next PD and keeping weakning strike always up ,that was always enough to keep every boos hooked on me . Also i never used Showdown Banner just for reducing the meele hit , never had the need for it , but against mob/bosses whit magic attack due to his part in raising all the magical resistance , so my advice is to save it for the magical attack , if you can stay alive and safe whitout using it to reduce meele damage .
Again for aoe tanking ( assuming we always have PD up , as you should ) i'll just build up 2/3 charge then activate Edge of Righteousness and release wirlwind chop , and if there's any mob still waindering around any of the 2 shield stun fo grab em back . If your party is aoeing tho , somethins i had the need to to add HBS to EoR for more sustained aggro all around the mobs .
As i said before that's just my own gameplay which may not be your or anyone else , just giving another point of view