Correct size for mai sail blocks

[essebibi]

Hi,
I would like to replace the mainsail blocks with new ones, but I have a doubt.
The boat is a 1977 Victoire 822, so just 10m2 of mainsail.
Many people told me that they it's better if:

- with ball bearings
- maximum allowed rope diameter should be more than the one used

I want a 10mm rope, 8 it's too thin to handle, so I was looking for a ball bearing set with maximum rope diameter of 12mm. Not so easy...

Selden BBB60 series would be perfect (ball bearing, price), but maximum diameter is 10mm. Same story for the Ronstan 55 series
Selden PBB60 has maximum size of 14, but no ball bearings.
Harken element series has no ball bearings. Harken premium ones are too expensive, and mostly 10mm.

Does somebody know something that fit my wishes?

Or if nothing can be found: which tradeoff is better? No ball bearings, or rope size at the maximum allowed?

Many many thanks

Stefano

[essebibi]

At the end, I found by a local retailer the Viadana ball bearings blocks.

Price very low, they look like a copy of the harken for a fraction of the price. Quality seems quite good.