How do you change settings on a wrist-mount? Even if you don't need to change the screen underwater, you still have to do stuff like set the 02 percentage topside. Or do you have a left arm you can strap it to?
A computer isn't something you need to look at continuously. Most people do so for their final ascent, but you can learn to gauge your ascent rate by watching bubbles or just through practice and check occasionally to verify. While it wouldn't be my recommendation for a 2-handed diver, a console clipped via retractor (or bolt snap if you want to be a purist
) makes a lot of sense for your use case. You can even get an air integrated console computer with all the fancy features, although they cost a lot more than separate computer and spg.