Probably depends on how long it takes your dealer to get the replacement harness. Might not be fast although I really don't know. Also depends on how long you have to wait before they put someone on it. In reality, the harness replacement shouldn't take more than a couple of days if they have someone who knows exactly what they are doing to do the work. Perhaps they can do the diagnosis, order the parts and give you a call when they are ready to start on it. No point in having it sit at the dealer's.
Once they have done the diagnosis, ordered the replacement harness and you are waiting for an appointment, see if they have a problem with you "patching" the harness they are ripping out anyway so you can safely ride while you are waiting.
If they don't have someone who knows what they are doing, find the problem, fix it yourself and move on! A properly installed (factory) harness with repairable burnt "spiders" is vastly preferred to one installed by a shop monkey with only a vague understanding of anything electrical. Too many ways to **** up the install if you don't know what you are doing. Anything from future issues with chafed or pinched wires to just plain wrong and non functional.
My S4 was fixed in the recall before it had a problem but I had later issues with S6 and another non-spider ground wire. (Fixed these myself)