I tried calling CZ, but didn't really get an answer...

Will a 50mm objective scope fit on the CZ 550 with the standard rings, or do I need to go to the medium/tall rings?

Anyone have any experience with these larger diameter objectives on the CZ?

Thanks in advance..

I assume you mean the standard CZ rings.
They are actually "high" by American standards,
"low to medium" by European standards.

IIRC:
I have used the standard CZ rings in 30mm scope tube diameter, with a 50mm objective lens scope.
Works.

I have used the standard CZ 1" rings with a 50mm objective Sightron scope too.
Works.

All of this assumes you do not have some weird, huge ocular bell that blocks the working of the bolt handle.

Medium Warnes and Talleys might even work. They are lower, but I do not dare try to "recall" on the fly, from an iphone, on those.

The CZ rings are pretty high relative what most of us are accustomed to here in the US. The ones I've got I think are medium and work fine for a Nikon Monarch Gold 2.5-10x50 on my CZ .375.

LWD