I've used compact nylon covers on all of my Beemers made by E-Z Tourinig out of Madras, Oregon. For the Cheiftain I bought the Traveller XT cover as per the company recommendation. It almost completely covers the bike and if I removed the back rest I think it would. I do lower the windshield all the way down to get it to go completely over the front fender. They do make larger covers as well. There's no sales tax in Oregon and a couple of nice older gals own the company. This cover fits into a 11" high by 10" wide bag and I've used the stuffed bag as a pillow when I forgot my camping pillow on the road. I paid $105 for it. They have black or blue as well if you care to try and match your rides color.
Depends what you mean , cost or protection? If you mean cost well I went that route and cover deteriorated and caused some paint issue on chieftain, so lets phrase cost effective, I purchased factory one cover and worth every dime it is the nicest and well made cover I have ever purchased and need do I say its better than the other guys which I owned for 15 years and had factory cover which needed to be replaced ever few years.