Both brake springs on your rig go behind the brake pads - toward the differential, like your pic of old ones above ( which is really a pic of the backside

). That illustration above is for later drums that have the pad retention clips in the middle of the pads (that’s what that hole is for). Better illustration for your rig:
View attachment 3179558
Also, do your new cylinders have the ramped adjusters? If not, and your old ones do, swap them out (easy to thread in/out to swap out) and install so the ramps slope downward toward the axle, i.e. high is to the outside. This really helps the pads to fully return to neutral when brake pressure is relaxed. I wouldn’t mix 9mm and 10mm lines/fittings, your messing with varying the brake pressure and therefore rates. Go either one or the other.
@Rainman doesn’t make brake lines anymore, but maybe he’s got some leftovers he’d be willing to part with. Also
@65swb45 or
@pardion .