I believe the heritage rims are the standard stock offset of +60mm so running those with a 1.25" spacer puts you 0.4" closer inboard than running the +18 offset you had before.
They will fit with no problem, but I am not sure how specific you are trying to get or what you are trying to test with other methods. For peace of mind I can show you via the calculator how they would work compared to your current setup and a setup that is common for others.
Comparing them to...