Short Answer: One hotbar.
Long Answer:
I have one hotbar visible at all times at the top of the screen. I change between three different setups for that bar based on whether I'm solo/group/raid. In general, they all have the basic heals and only the last 5 spots change. I use the keyboard exclusively to access these.
IIRC, the three setups vary in their inclusion of things like the OH SHIT macro (death save + other goodies). For example, that has limited use for solo play. Other examples are like Divine Arbitration, the fate line, the daze/stun and the stun heal. Those are all useless in some settings, so I don't always need them up. I macro reverece and the new ward together, but only on the raid hotbar.
I macro all my nukes in a specific order to "Q", along with autoattack and the HO starter. I macro my big three debuffs to "F".
I keep cures (99% of the time I use the Profit group UI mod for cures), clickies and rezes on two hidden bars bellow that. I usually just use the keyboard shortcuts (CNTRL + ALT) to access those. I also keep three macros for quickly switching between solo/group/raid gear here. Sometimes I switch during a zone in between fights between DPS and max heal gear.
I have a fourth hidden bar on the bottom of the screen for buffs.
I like to minimize the amount of UI I see all the time. This gives you a good idea:
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