It has been a long time sense using Slic3r I have upgraded to Prusaslicer this little jewel was created from Slic3r it is one of the best free slicers ever.
You should be able to import your Slic3r profile and update using all the new and wonderful functions and create a new profile that will print even better.

I updated my Hictop to this perfectly wonderful slicer and found that even my cheap printer can print perfect models without much effort.

To answer your question my : Infill / Perimeters overlap is set to 15% this is really not needed though proves to give stronger model.