I know you already bought the towers but I think the biggest reason I'm going with the collar for mine is the fact that if something goes wrong with the freezer, you can literally swap out the collar onto the new freezer with a minimal amount of work and the old freezer isn't damaged in any way.
The thought of cutting holes into the top of an insulated freezer lid gives me the willies, it can't be undone and you will have to do the same amount of work again if you need to replace the lid. Plus, try explaining those holes to the warranty company.
And hey, I'm not lazy, I'm
efficient™