The 160/340 spring is ridiculous to me. I like anything from 100-maybe 140 start at most . And 310, maybe 320 finish. So, a 110/290, 100/305,120/300,120/310. Etc..
in other words, if you can’t pull weight with a 120/310 spring, take some out. Don’t add a heavier spring for more resistance. Just...