I use 2 hotbars.

The primary hotbar for all healing and support skill. I can run through all dungeon by using just this hotbar alone. But most of the time I will switch to attack mode to help dps.

From left to right:
Instant-raise, soil, leech, succor, Fey illu, sprint, protect, rouse || physick, lustrate, adlo, drain, virus, whispering,Aether Flow, eyes4eyes

The secondary hotbar is meant for solo, attack, and some support skill that take time to cast.

From left to right:
LB, Instant summon1, Instant summon2, Cleric stance, miasma2, sprint, shadow flare, sustain || physick, stoneskin, adlo, drain, aero, macro all dots, aether flow, ruin2

The location of physick, adlo, sprint, aether flow, drain are the same in both hotbars in case of emergency.

for controling pet,*just toggle pet hotbar.

For me, the combination of R1+[triangle, square, left, up, down] are easiest, quickest and most comfortable to press. So I map skill that need to activate quickly in those slots.