Free blocks on Emty CD

Is it safe to say theat all emty CDs have around 359000 free Blocks,
or can on different CDs be different?

Never heard of 800MB CD’s?

I think the savest way is to query Nero about the
number of free blocks!

Although that sounds like a reasonable figure, you should really not assume anything and do a check every time. For instance, there are those business-card type of discs which do not have that kind of capacity.