Originally Posted by
Hatsuwr
.....PC and yoke angle seem to be at least partially dependent upon Attachment Point to Pivot Point length and the angle between PA and PS which are determined by the geometry of the brakes.......
The straddle cable length and the pad to arm distance the main controlling factors.
And as noted by [MENTION=391685]Andrew R[/MENTION] Stewart "...placing the thicker concave spacer between the pad and canti arm will bring the arm angle out to come closer to a right angle with the straddle cable when the pads contact the rim."
Your current brakes offer all of the adjustment you need to make them perform as well as any rim brake possibly can.