I’ll just post it first then explain it next:
#showtooltip Hammer of the Righteous
/cancelaura Hand of Protection
/use [spec:2,bar:2]Guardian of Ancient Kings
/use Hammer of the Righteous
Of course I choose the question mark for the icon and select which icon to use by #showtooltip. The /startattack is so when a mob dies I change over to a live one immediately. The /cancelaura Hand of Protection is so the others paladins can BoP me and one button takes it off without some inconvenient right clicking on a buff. I highly recommend all tanks macroing that into their most used abilities. The rest using [bar:2] is interesting. I have “full control mode” of all abilities when action bar 1 is showing and “lazy mode” when bar 2 is showing which uses most my off-gcd abilities on cooldown. I find just flipping between action bar 1 or 2 is too convenient to pass up between say trash/boss or raid difficulties.