For two-railers where I prioritize hitting the OB with the highest probability (such as your example), I use the midpoint parallel shift method, but with a thoughtful way of adjusting from it by feel. After doing the parallel shift and standing at the baseline from it, I do the following:
(My base line for tip position is 1 tip of running side, and maximum top. I only adjust from this if the hit can't be made like that, e.g. if I need check side or swerve)
I visualize the following three lines:
CB -> First rail impact
First rail impact -> Second rail impact
Second rail impact -> Target impact
Then, I consider two things:
1. The angle that the CB is coming into the two rail impacts. I observe how much the running side will alter the angle off both the first and the second rail based on the speed I intend to shoot at, and how flat the angle is towards those rails. This takes some experience and feel to be able to judge well and depends slightly on the table as well, but the basic idea is that faster speed = more angle change, and that flatter angle = less angle change.
It is important to consider the loss of speed during the balls movement between the first and second rail, especially if the distance between them is long and you are shooting pretty softly.
Now, after considering those things, I will have a feel of whether the angle off the 1st and 2nd rail would make the overall shot miss long or short from the OB, and by how much, if we ignored the other one and assumed the other rail performed like a perfect mirror.
(Will add image here later for clearer example of what I mean)
2. The difference between the distance of the path from 1st to 2nd rail, and from 2nd rail to OB. Now that we know what rail impact makes the CB go short or long, and by how much, we can consider the ratio between the distance of the paths after the two impacts, to see how much they get to affect the shot as a whole.
For example, if the ratio is 1/4, such that the path after 2nd rail is 4x longer to OB than from 1st rail to 2nd rail, whatever shortening/longening happened between 1st and 2nd rail has a 4x smaller effect to the whole compared to the second impacts shortening/longening.
So, to simplify the whole thing, considering the both individual rail impacts shortening/longening of the CB path, and then considering a ratio between the two relevant path distances to amplify the shortening/longening effects strength towards the whole shot, will give a very informed feel for how much to adjust the shot. This adjustment is simply aiming some amount to the left or right from the baseline.
I almost never miss two-railers with this style. To practice it, you can throw balls on the table and just try to hit balls with this method from varying positions. If you put in the thought, you will notice fast improvement towards the accuracy of the adjustments.
It's not really a system due to no math to follow or formulas involved, but rather a way of breaking apart the shot, absorbing all the relevant factors that matter, and giving them to your subconscious to let it make a more informed decision for how much to adjust, instead of just looking at the shot and doing the adjustment 100% intuitively.