No point use them at lv186. For me it’s a waste use cards at reset experience, i mean: completing some maps for questing you lv up easily.
So, just do lv181 and then use all lv8.
From 181 to 186 you need about 120 cards if I remember correctly. So you need 17 lv8 card, so you can do monster achievement.
Or you can still grind (1/2hrs to lv up I think).
Or use some lv9 and then do the 190 dungeon until 200.
Use lv9 cards after lv195/200.
My alt is an archer, and for lv up I use a white weapon bow (they are more easy to farm).
Red weapon are likely impossibile to obtain at this lv.
Some of Violet weapon are World Boss Drop (so, if you don’t know when and how it works is impossibile to obtain).
And some Blue weapon we don’t know where to get them xD
EDIT: and yes, Roxona East/West Building is good to grind. You can obtain nice recipes, know new mobs, do monster achievement, explore the map… A lot of things!