Need some advice on Fire based minions.

So, i took my chance to test my first necromancer build, and it's actually doing pretty well, the only thing bothering me is that i can't find a good Spectre minion with good fire damage spells, i've been running around with 5 Infernal Sentinels and they do tons of damage, but i think it can do better, i see the damage is getting lower and lower from tier 9 maps and so on.

So i was wondering if someone could enlighten me with a list of good Fire damage based minions i can try on (it has to be spell based skills cause i'm using spell echo on them).

Flame Sentinels or Solar Guards are your best bet.
As you go up in map tiers, you will need to re-summon them.

TV is the only efficient end game choice for fire spectre when you struggle with dmg.