If you want one, I can help, PM me. NAPA probably doesn't want to deal with potential international lost shipping claims in these times. Also, it looks like on that page they are not available to NAPA for anyone. I'll inquire on Monday to see if they are available from the manufacturer.
I wouldn't say they are waterproof. After connecting the wires in the setscrew terminals, I pack the boot with silicon seal as I slide it over the connector half. At the joint between the halves, submersion could short it, but then you have bigger troubles than a short!