Once you have done your experimentations and have copied the final template think about your next steps as a first pass.
Use fake / latin text. Leave the WIX images in place.
Put your focus on structure , links, buttons, forms and navigation.
Pick the pages you DON'T need to launch and set them to non-viewable mode.
For the pages you will want complete for launch start with replacing text only.
For your launch pages first replace the images you know need to be replaced.
Next, consider replacing other images that might work or might not.
This should all take less than 8hrs.
You'll still be doing a polishing run, so you can leave things a bit loose.