For high dInts, T4s have Int multipliers of about 3, so 4 Int is worth about 12 base damage, and thus Doris slightly edges out the win (13 base damage vs 12). As dInt drops, that 3x multiplier goes down to the T3 spells, and then the T2 spells.
So:
dInt 100+, Dosis wins on T4/Ga3 and under
dInt 50+, Dosis wins on T3/Ga2 and under
dInt under 50, Dosis wins on T2/Ga1 and under
In all cases, T5/Ja do better with Ombre
In all cases, AM/AM2 do better with Dosis
Given something like 130 int from gear (mainly Hagondes), you should be at 50+ dInt for almost everything except (possibly) Delve bosses (and probably even them, assuming Impact is being used, along with various other possible int buffs/debuffs), and 100+ dInt for all older stuff (including old, high-int NMs like Kirin).
As such, I'd always recommend Dosis for T1/T2/T3/Ga/Ga2/AM/AM2, and Ombre for T5/Ja. The only questionable entries are T4/Ga3. For those, though, on the borderline cases (dInt between 50 and 100) the difference probably won't be more than about 10 damage (out of 4000), so I'd select based on whether you expect to encounter more low dInt situations (under 50 dInt; use Ombre) or high dInt situations (100+ dInt; use Dosis).
For Erlene, with 3 MAB, relative value depends on total MAB. With 220 total MAB (including trait), Erlene basically ties with Dosis on T5/Ja, and is worse than Dosis on all other spells. With higher MAB, Dosis always wins on all spells. With lower MAB, Erlene has a very marginal edge over Dosis on T5/Ja. You can drop to 140 total MAB and its lead is still only about 10 points on 3000 damage spells. As such, I would consider it completely obsoleted by Dosis, leaving you only with the question of Dosis vs Ombre.