Outdoor Sealants?

To seal the papier mache for outdoor use, is there a preferred sealant? What should we look for in selecting a sealant for outdoor use? I have in mind some projects for holiday decor that would be outside for several weeks at a time. I'd love to find something that could withstand the weather and sun for longer periods, so that papier mache might be used for garden art.

From my reading, it seems like marine varnish (something like this: https://www.amazon.com/Rust-Oleum-207008-Marine-Varnish-1-Quart/dp/B000C011CE/ref=pd_lpo_vtph_60_bs_img_1?_encoding=UTF8&psc=1&refRID=EV30B08DZPTTCGANHTMA) or roof sealant (https://www.amazon.com/Sashco-Through-Sealant-Quart-Container/dp/B00110A8D2/ref=sr_1_1_sspa?ie=UTF8&qid=1505754776&sr=8-1-spons&keywords=through%2Bthe%2Broof%2Bsealant%2Bclear&th=1) is your best bet. These are fairly noxious, but they just work better than anything water based if you really want to protect your work from the elements. This is a good, if somewhat long winded, post about a very thorough experiment on the subject: http://www.papiermache.co.uk/articles/waterproofing-papier-mache/1/