how to set eth to certain hash and then use what is leftover for ton? (beginner question)

[ares0027]

i am sorry if i couldnt explain it well; i have a single gpu, an rtx3080 lhr, if i just mine eth it can reach 65mhash, if i just mine ton it reaches 4200-4400mhash, if i dual mine it RANGES between 30-60mhash eth AND 300-2900mhash ton. if i close it and run it again it changes, i have to find the sweet spot by randomly turning it off and back on again until it gets 59-60mhash eth AND 1700-2200mhash ton, this is the best stat i could manage to get.

so here are my questions;
1- how can i guarantee i get those stats all the time, why is it random? i am not changing anything, any apps, nothing is running on pc, nothing is using gpu, why range is too big?

2- is there a "push eth until you get 60mhash and then use rest for the ton" setting? i dont really care about ton, but it is still better than solo if i can get 1000-1500mhash with it on the side