I will later post about blood offering being next to useless for this variation.
A good solution would be to make the damage bonus of blood offering give more damage exclusively to your command grabs the lesser/more sun charges you have, something like;
L1 BO 12%
L2 BO 20%
L3 BO 25%
The problem right now is that blood offering doesn't really do much outside of catching someone with a F2. Everything else receives a very slight damage bonus except his hard hitting combo starter in F2.
Command grab damage is
10% - 3% increase
16% - 5% increase
20% - 4% increase
As you can see, the damage gets noteworthy at after lvl 2 due to the scaling.
The metagame of blood offering in Sun God is that you desperately want your F2 to hit and your reward is 4-5% additional combo damage for every buffed F2. The problem with is being that any other moves do almost nothing because they don't have high base damage and the limit of your buff's duration is 3 hits, block or hit.
It all comes down to BO being very situational and granting small increases in damage unless you land a F2 which actually makes the 10% you sacrificed turn into damage dealt at the ratio of 1,2.
( BO ) F2 ( BO )F2 ( BO )F2 B12 Sun Choke L3 = 44% that's the damage of your 1 bar BNB for no bar at all
BO X3 F2 F2 F2 B12 EX AA B12 Sun Choke L3 = 55%, 11% more damage for one bar
This is the part when sun/god ray comes in. You always want to threaten with these, normal ray gives about 1,5% if your opponent comes running at you with you having to respect his normal, god ray gives 3% in the same time.
While that's good and all, you need time to set up blood offering and the rays. You no longer have the luxury of ray being done off of a knockdown because you must conserve your damage buff and are pretty much forced to either do a long recovering ray in neutral or not at all. In theory, it's very easy to say that you do blood offering and use the rays to recover your hp but in theory that is simply not practical. Are you going to use a potentially punishable beam with slow life gain or a slightly faster one with good life recovery at the cost of meter?
Assume you do get your ex ray out, you've spent a bar and how are you going to capitalise on damage? A tick throw wastes 2 buffed hits on a mixup for slightly more damage, other hits give you about 5% added damage on your regular bnb.
F2 is the only combo starter worth having with at least 2-3 hits left on BO. We've already discussed the meterless and metered damage of this unsafe move. EX Ray is 1 bar, your 55% bnb with all 3 hits, an unsafe launcher and 1 bar of meter 55%. You used 2 bars of meter and restricted your use of normals for 55% when Kotal gets 44 with simply one and no setup required at all. No gimmicky self-hurting buffs and needing to activate ray and hope the mindgame turns out in your favor.
The only way I use blood offering at this moment is with 3 bars left, fishing for armoured command grabs for 60% total as a total gimmick because anyone with a brain can see that I've forsaken his normals entirely.