Woodie .... weights can certainly help. They also keep you from having to let out so much line, &/or use heavier jigs to get to that depth.
I've used three different "styles" of weights when Pushing jigs ... barrel sinkers, in-line trolling weights from Crawdads Fishing Tackle, or Bullet Weight's Mr Crappie Troll-tech weights. (depending on how I'm rigged & how much weight is needed)
Fished with a buddy of mine & we rigged with 1oz weights, 1-2 jigs (1/8oz), and Pushed at ~1mph ... to get the jigs down to around 12ft deep with about 25ft of line out. Our lines were not running at a 45deg angle, best I could tell, so our depth is just a calculated guess on my part. I use the Pythagorean Theorem to calculate depth ... multiplying length of line out (below water's surface) by 0.6 when lines are running at a 45deg angle. So, since 25 x 0.6 = 15 ... and our lines were at a slightly shallower angle, I calculated the weights/jigs to be running slightly less than 15ft deep. Another way to figure it is every 5ft of line out below the surface would equal 3ft of depth, if the lines are running at a 45deg angle. We trolled over a flat that was 15ft deep in spots & the jigs never dragged bottom, so I'm fairly confident that we were not reaching the 15ft depth with our jigs.