@Mouette, you can source a very good hard black Arkansas 8" x 2" x ½" from wnun5791 on eBay for AU$125 plus AU$14 postage. He is based in Jingili, NT. According to some SR shaving friends who have bought these from him, he provides great customer service.
I have one of his HBAs that I bought second hand for AU$80 including shipping from a knife sharpener in Sydney who didn't know how to use it. It finishes an edge beautifully.
As for an uneven bevel on one side, that is only aesthetics, shouldn't affect the shave quality. Provided your whetstones are flat, the unevenness is most probably caused by uneven wear on the grinding stones when the blade's hollow was being ground.