From personal experience leveling an amistr takes a lot time and work. And Ive yet to end up with a filir thats suited any of my builds.
Now I don't know too much info on the vani + brewer combo. But Ive heard from multiple people that it gives a small boost in the potion creation. I know you'd rather not have another vani, but they really are very helpful, and if you luck out like I did and end up with one that had an even amount of str and int you shouldn't have to worry about fighting something with high magic def. (He suited me well RIP poor Petit Danone! I regret going for more of an int vani)
Also if you can find the time to make a lif loyal (I know I know everyone and their dog does this combo) they really are the fastest way to make an alchemist to 99.. A very cheesy but fast way.
