I like the arm triangle a lot, but it's harder to finish when you use a near-side side control set up. When you set up the choke from mount, the rotation of your body to side control adds a lot of pressure to the choke, even moreso when you set up the choke from far-side side control. When you sink the choke from near-side side control, you don't get that extra torque, so it's much harder to finish the choke from here. It's possible, but it's harder.
The better option that I see for the near-side side control arm triangle is to use it to bait the guy into giving up his back. If he's in a position to give up the arm triangle, he's just as easily going to give up his back (i.e. his near arm is up and across himself). Sometimes I'll use the nearside arm triangle as a set up, the guy will either roll away from me, giving up his back or giving up a near side arm bar, or the guy will roll into me, giving up a far-side both-arms-in arm bar (or the back for that matter).