Preparing for the wiring harness

I’m now totally committed to making my wire harness, or should I say knee deep! It’s now all apart and I’ve marked every wire end. Actually it’s quite educating because I never really knew much of anything about the wiring. Last time I just ordered a new one and it came with the fuse board with everything hooked up and all the ends marked. From this perspective it all starts making a little sense to me with where wires are going and why. Today I ordered all the various colors and size of wiring, between 2 places I got all the colors. I ordered all the sleeving material, heat shrink, fittings etc from several sources and in about 2 weeks I should have everything. I will probably replace all the relays. What is the best source for those?