Judging by your topics and posts, so far you read a lot about the eye in general to understand the science and experimented with trading off your cyl to sph (which is not EM specific, since that’s what optos do, too)
EM definitely doesn’t recommend living with blur for distance vision, or not using any corrections for close up if the prescription is -8 or -9.
The healthy distance (good posture, etc) from monitor is 50 to 100cms. As differentials are meant to challenge your eyes with some blur, I always suggest to set the blur horizon at minimum 60cms, so on a day when one has to skip the blur challenge, it is still possible to work at a healthy distance.
And anyway, 1) you don’t need my approval on what distance you choose 2) there’s no gain for you by bargaining for a 10cm-discount from my rule.
I’d suggest you start by getting glasses that are perfect for real distance vision = you can see well immediately at any time at any distances (even when driving at night, too). There are situations when you will have to see well immediately.
Then spend a few weeks with measuring your distance to blur consistently to spot the patterns - how much different lights, tiredness, or the number of hours spent in front of the monitor influence your vision. I’m afraid there is no shortcut on this part as this is specific to you.
And then define your healthy distance from monitor and get differentials that are at the edge of blur at the “healthy distance + 10cms”.
Finally, I would also recommend spending less time in front of screens and more time outdoors.