Just use angelite or topaz until 5+ storm appears. Just so you know, you can place 5+ storm anywhere, even your mainhand weapon (ie wand) but you cannot put that affix on any offhand weapon.
This same thing applies for any +5 skill. If you use an offhand affix (+5 stealth) , you can place it anywhere on gear, EXCEPT the mainhand weapon.
This is just dq logic and kinda common sense but here's this guide to help you understand more about this. It also tells you what affixes cannot be got from amethyst and ruby as well as obsidian restriction on the block affix where you can only roll it on an offhand weapon. I hope this helps you and good luck on your dq adventures