Belt doesnt work with Arcane, only with multi.
And yeah, playing without sidewinders and with patient sniper now is basically completely reliant on RNG, Ive been playing it alot in m+, mostly on volcanic weeks and sometimes you just dont get marked proc for 15 seconds and spam arcane and aimed without vuln and then you get three back to back, which you cant even proeprly use, because you dont have enough focus to get good benefit from it unless you also get lucky LnL and even then, the spec is doing significantly lower dps on single, like worse than eleshaman single. Has sick Trueshot aoe burst tho, wish I had boots, would have played the spec more in m+