We (current co), and my previous company have used both Epicor Professional Services and 3rd party consultants to advise us on process best practices. There are good consulting companies out there, with experts in the various areas (not just customizations). Call, and interview. Many will also host regional Epicor Users Group meetings (in person or remote). Once you find someone and stick with them, they’ll get to know you better and their advice will skip a lot of that up-front learning of your special way of doing things…
Also, contact your CAM to have Epicor come on-site, and do a free Value Exchange Workshop. You’ll both learn a lot about your company and processes, and will get a few easy wins (and some hard ones!).