Using an undersized Kryosheet?

I've got a spare 33mmx33mm Thermal Grizzle Kryosheet and a 5950x that needs thermal interface. The correct size is actually a 38x38 but I was thinking since the AM4 cpu is actually not centered under the IHS that I could probably get away with not have the IHS completely covered anyways BUT I thought I would ask the internet how bad of an idea this is.

You still want to cover the rest of the IHS, otherwise heat will build up in areas that aren't covered by the Kryosheet. I would at least still use TIM to cover the areas not covered by the Kryosheet.

They got me once with that "cut it to size" bit. Yeah you can do that but that's not how they sell them. Walked into a Microcenter to buy parts, they only had one size of Kryosheet, I figured I was just supposed to cut it to fit without checking... nope. Bought a square one meant for AMD when I needed an Intel rectangle. Oops. I used it on a later AMD build. Seems to work fine but the AMD build isn't much of a test - 9600X, and I don't bother OCing procs anymore. I'm generally GPU bound so it's not worth the hassle. For the Intel 285K build I just used the Arctic paste that came with my Arctic AIO. Also seems fine. Didn't get too hot on a Prime95 small FFT run.