Budget blade vortex assassin damage conversion questions

I love blade vortex, and this league has been great for crafting the sort of gear that makes it exceptionally powerful. Explodey chest, power charge helm, godly wands or staff, etc.

My question revolves around damage conversion. Rare 50% conversion gloves for fire and cold are very expensive. Avatar of fire negates sources of extra phys/elemental dmg as chaos, such as atziri's flask or Grim Oath notable. Ideal mods on circle of anguish cost 10 ex, and for the cold version are 3.5 ex. Crafted bows seem weaker than void batteries or crafted wands/staves. Physical ring mods are quite cheap. Damage conversion mods on watchers are pretty cheap, while ideal extra damage stuff for builds that get 100% conversion by other means are out of budget.

Budget cold: 25% convert on gloves or 50% on hrimburn, 40% on watchers, 25% on quiver
Budget fire: 50% avatar of fire, 40% watchers, 25% gloves, 50% quiver

So for cold convert, you either settle for hrimburn and 90% conversion or use bow/quiver, and for fire you settle for 90% conversion or use avatar of fire or bow/quiver. In both cases you probably either give up circle rings for rare rings or use suboptimal mods. Possibly mana cost reduction circle mod could open up room for better auras/heralds.

For cold there's also the possibility of converting to lightning with gloves, support gem, and either quiver or watchers, then using call of brotherhood rings.

There are examples on poe ninja of pure physical, cold conversion, and fire conversion. I'm confused on which offers the highest end dps with budget options. Should I stick with straight physical dmg, or convert to fire or cold? Should I settle for 90% conversion, use a bow, or use avatar of fire?