Ancient magic for bossing

I came back to rs3 a couple of months ago, and I've managed to get the stats for some low level bosses (mainly gwd). I've been using magic at Kril, since he has the weakness to fire spells, and I've also been using magic at Zilyana. Do I want to be using ancients instead of standard spellbook at these bosses? I know I don't want to use blood spells at Zilyana. Also, should I use blitz, or barrage? I play on revolution (really convinced me to come back tbh) and according to the wiki the burst and barrage spells don't act as aoe spells on abilities. And since damage scales with level, wouldn't blitz do just as much damage as barrage, except for the occasional auto attack?

Thanks for the help.