Correct way to bleed Suzuki opposite piston calipers ?

[sidetrack]

I struggled for about half a day to bleed my late 80’s GSXR rear caliper. It was dry and I had to get fluid into the line first but try what I might could not get pressure only a bubble or two but no fluid coming out. I then stripped the master cylinder again as no bubbles were visible in it, it seemed to help but still required a lot of bleeding. Eventually after bleeding at both nipples I got some results. What was the reason for this design ? It’s complicated and takes twice as long or is there a trick to bleed both at the same time maybe ?