A5 shards rationing

As we all know a5, WSK in particular, allows for the fastest xp progressing.

That was an important part of my sorc's progress to 99, and since then I dedicate most of the shards to the next highest char, the self wield Infinity zon. She's 97, damn slow, it will take forever to get to 98, probably never to 99 (hello disconnect). And she only can gain some marginal survivability progress now, all the dmg is long maxed

So I wonder, maybe it's better to dedicate the a5 shards to other chars?

strafezon, 96, also damn slow, main Herald hunter, still can gain some dps
Lightning Fury zon, 91, top build speaks for itself, but not that good vs heralds unfortunately, can gain both dps and survivability
enchantress, 89, very strong but annoying with prebuffing, can gain some QoL from longer Energy Shield and resilience

icemaiden, Plague zon, Exploding Arrow zon, fendzon, warlock, pally and necro prly don't deserve the good stuff

How do you go about it?