Let's see. removing fender and reinstalling 2 hour or so. Taping took 10 mins. I was not looking to get into a project that took all weekend. I painted aircraft for 20 years, and big jobs just are not my thing anymore. However I do agee it is easier to spray soming that is on a stand or in your hand. You have more control.
Nice job, but it probably would have been a whole lot easier just to remove the fender before painting rather than worrying about taping. Before I painted mine it did a full cycle in the dishwasher and then a rub-down with acetone and finally a prep-wipe. I used Krylon Fusion gloss black. 2 years and no fading or chipping yet.
Polypropylene melts between 320 and 330 degrees F, so I wasn't too worried about the hot water. Plus my water heater is set to 130F.