What I have found out over the years...
WELDON touched on the subject of Valseline and any other petroleum based product. I concur. A no-no in my book.
A silicone spray is messy if only wanting to spray the rubber seal without all the over spray. It's a PITA to clean up where you don't want it. And it doesn't seem to last very long. If any of that matters to you.
I use a Teflon based grease, hand applied, on my slide seal and cargo door seals. A little extra elbow grease, but I have had good luck with the product. As carson mentioned, available at swimming pool supply stores. I don't have the problem with road dust and grime due to being permanent. But, I just wipe the seals down every other year or two with a paper towel, re-apply the grease with a clean paper towel, forget about it for another couple of years. I just replaced the original 1994 slide seal and the cargo door seals are still fine. I'm sticking with it, UNLESS...
92GA brings up a product I am unfamiliar with. I shop quite often at a local NAPA and will have to inquire about Sil-glyde. Might be something to consider.
A similar subject concerning slide seal lubrication has been addressed before. You might want to search the site under that title and do a little research. Might be some answers for you.