I’m also a Back to 20/20 student
My take on your question:
Starting point (OD/OS): -0.75 -1.50 / -1.25 -1.50
If this is converted by an opto, it will be -1.50 and -2.00 by using the opto’s formula of 0.5D cyl = 0.25D sph
Going by the sph only conversion, you should be totally OK to go without differentials.
But! because of the high cyl compared to sph, it will be your personal experience that will determine if you can drop glasses for close up activities completely.
Your glasses have -1.5D extra correction added on the horizontal or vertical line (depending on your axis). If you have worn these glasses long and found them comfortable, got used to them then you may have got used to this uneven correction within each lens / eye. If you are seeing double without the glasses or if you get headaches without the glasses or if you don’t have double vision or headaches but you are not more than 45cms away from the screen, then it would make more sense to drop the cyl in steps (e.g. drop sph completely and keep some of the cyl). If you are perfectly happy and OK without corrections in front of the screen at a healthy distance (i.e. can utilise your peripheral vision, too), then there’s no need for corrections for close up.
As for glasses in general, to work away the last diopter I’d recommend wearing glasses for real distance vision time, i.e. when you are looking at distances greater than 10 metres. If you are going without corrections for the screen, then make the distance glasses without cyl. If you realise you need some cyl glasses for close up after all, then adjust the cyl in the distance glasses accordingly.
Reducing sph is mainly the work of the eyes, reducing cyl is 50% eyes and 50% brain - coordinating the overall image along the new and changed inputs from the eyes individually. (cyl causes an oval shaped distortion to the image, when you drop cyl completely the oval becomes a circle - that’s tough work for the brain to fine tune again)