Just moved to a new house, replaced the old Moen faucet in the kitchen which was clearly never installed properly in the first place. I grabbed a Delta Owendale single-handle faucet from the Depot and went to install (I'm no expert but have done a few faucets in my time).

For context, it's a double offset sink with two holes in the granite countertop, but due to the offset it won't work with the included escutcheon. I went for the single-handle installation and was confused that it didn't have any sort of gasket or other seal solution. The kit came with a "thin deck aid" which requires a three-hole configuration and did have some little gasket piece, but that piece didn't fit in the faucet when not using the deck aid.

The Delta instructions are somewhat generic and from what I can tell don't really call for any gasket for single-hole install, using terms like "if your faucet has a trim ring" (unless I'm reading it wrong, which I could be). So I just did the install and tried it out - and of course it does leak when it gets splashed. I have called and emailed Delta multiple times but can't seem to reach anyone or get a reply. There was nothing in the box which would have worked as a gasket so maybe they just forgot to include it.

In any case, I'm wondering where to go from here. Is there a generic gasket that I can use, or must I continue trying to reach Delta to get whatever part may have been missing from my box? Or should I just use some silicon sealant around the base and call it a day?

Forgot to mention, there was also a soap dispenser which I installed in the hole that used to hold the Moen handle, just next to the faucet. It does have a foam gasket built in, but it also leaks. So I am thinking maybe a sealant would be the way to go regardless - if so I need recommendations for what product and how to apply it, as I've never done that before.

Thanks in advance!