On a one-minute single-boss fight the build is 38/13/0. It goes deep enough into Holy for 
Holy Power and parks its spare points in Protection, where nothing touches a heal.
2/5
0/3
2/2
3/3
0/2
5/5
0/5
3/3
2/2
3/5
0/1
0/3
0/3
0/2
0/1
0/3
0/3
0/1
0/5
0/5
0/1
0/5
0/5
0/2
0/2
0/5
0/3
0/3
0/1
0/2
0/2
0/1
0/3
0/3
0/1
0/3
0/2
0/125320213225131051-50323The search found a build for each fight and faction, and none of them moves a point that heals. What follows holds for every one.
Why these talents
Six talents, 22 points in all, carry the build.
Healing Light adds 12 % to Holy Light, Flash of Light and Holy Shock, where Classic's left Holy Shock out. It multiplies every heal you cast and costs no mana, so it is worth the same 10.7 % on every fight.
Illumination returns half a heal's base cost whenever it crits, at a 100 % chance with five points. Classic's returned the whole cost. A critical rank 9 gives back 330 mana and a rank 4 only 95.
Here every heal is a rank 9, so every crit returns the larger refund, and the talent is worth 11.7 %.
Reverence is new in Forever. It keeps 30 % of your Spirit regeneration running while you cast, and nothing else lets Spirit pay inside the five-second rule.
On one minute your regeneration has little time to add up, so it is worth only 1.8 %, against 5.1 % on a three-minute single-boss fight.
Holy Power adds 5 % crit to Holy Light and Flash of Light, and 15 % to Holy Shock. Each crit is a bigger heal and an Illumination refund at once, so it is worth 2.7 %.
Divine Intellect raises your Intellect by 10 %, which is a bigger bar and a little crit. It is worth 2.1 %.
Divine Favor makes your next Holy Light a certain crit, once every two minutes, for 4 % of your base mana. The table gives it 1.9 %.
Flexible points
Holy Power sits in the sixth row, and each row asks for five points per row above it, so the six talents cost 30 Holy points to reach. That leaves 21 points our simulator scores at nothing. Spend them on what your raid needs:
Holy Shock and 
Light's Vigil. Holy Shock is an instant heal on a 10-second cooldown, the heal to cast while you move. Our fights never make you move, and it heals less per mana than Holy Light, so it scores nothing here. Light's Vigil needs it (see below).
Spiritual Focus, 
Unyielding Faith and 
Voice of Truth protect your casts from pushback, fears, silences and interrupts. Nobody attacks you in our fights, so all three read 0.
Infusion of Light takes a second off your next Holy Light after a Holy Shock or Flash of Light crit. The simulated rotation casts neither, so it never procs. Take it if you weave Holy Shock in.- Protection's first rows, Toughness, Precision, Guardian's Favor and Anticipation, are where the search parks the rest. No talent in Protection or Retribution reaches a heal, and Divine Precision's hit is wasted because heals can't miss.
Holy Shock and Light's Vigil
Light's Vigil is the 31st Holy point and your only party heal. At rank 3 you spend 1,340 mana and a 1.5-second cast to put it on an ally for 30 seconds. Your next Holy Shock on that ally then starts no cooldown and heals everyone in their party for 704. The heal takes Holy Power's crit, but not Healing Light's 12 %.
Paired with Holy Shock rank 1, that is 1,500 mana for one heal on each of five players. In our fights, Holy Light gets more healing out of the same mana on every fight, so no simulated rotation keeps the vigil. Two things the simulator can't weigh may change that. It heals targets at full health, so a heal spread over five players gets no credit for landing where the damage is. And the tooltip says Light's Vigil crits trigger Illumination, which our simulator doesn't apply to its heal yet.
What each talent is worth
The table simulates this build again once per talent, each time with that talent removed. Talents feed each other, so the rows overlap and their total isn't your healing. For one spare point, the last-point column is the number to use.
On every fight
Only the free points move between fights. The three-boss builds shuffle them among Divine Strength, Consecrated Ground, Improved Righteous Fury and the other Protection rows, none of which heals. The table compares each fight's build with this one.