Use faucet connector on toilet? Royal SSWW 1002 Fortuna

We are attempting to replace our toilet with Royal SSWW 1002 Fortuna. When the toilet it arrived, it included minimal instructions and our exiting 7/8" toilet connector (to the water) was too large. When we went to Lowe's, they sent us home with a faucet connector. This connector has a metal end to thread on the toilet (whereas all other toilet connectors have a plastic end). Has anyone used this type of connector before with a toilet? We were concerned about the metal nut stripping the plastic threads on the piece associated to the toilet.

The metal would be fine, if the thread is the right size and thread count.
Since toilets in America use a standard 7/8" connection, it's anybody's guess what yours is. It might even be a metric size.
I couldn't fine much about your toilet for parts. They don't seem to be sold in the plumbing channels.
We like to know that parts are available down the road. You will need parts some day.

However a faucet connector would be 1/2" and not fit a toilet which is 7/8"

He said the 7/8" was too large, so it was either a "bastard" thread or 1/2" ips.

Sounds like a bastard thread possibly metric...

Where did you find this beauty?

Looks like Overstock.com sells 'em. I searched the other day to try find the manual or some specs on this unit for you. All that I could find was a basic drawing showing overall dimmensions and the rough-in location. I didn't see anything on the specs for the threads.