Beautiful blooms!

As someone who loves what C. coccinea can do in breeding I'm always jealous of those who have the conditions to bloom them so well. Congrats!

Noob question here, but what is 4N?

Most organisms have two sets of chromosomes, one donated from each parent. This is commonly referred to as a diploid (2N) individual. You and I are diploid.

Plants have the ability to survive when their chromosome counts are increased. Any plant with an increased chromosomal count is called polyploid (e.g. 3N, 4N, 5N, etc.). Doubling the number of chromosomes would yield a plant that is called 4N. Polyploid plants often have larger flowers and plants, which is desirable. Some polyploids grow more slowly and have a tough time breeding, which is less desirable, so there are tradeoffs.

So does this mean that most compact to mini hybrids are 2N? (I don't mean to hijack the thread)

No, doesn't follow. Higher ploidy can lead to larger flowers for the grex, but it's a matter of degree - centimeters - and often better (fuller) form. Compact/mini hybrids have parentage that includes species that are smaller by nature... being tetraplioid doesn't change that. A further note... if a tetraploid (4n) is crossed with a diploid (2n) the result is often 3n - a plant with flowers that maybe larger and more substantial than a purely 2n version of the cross, but sterile - usually won't breed going forward. (There are plenty of very beautiful "mules" ) Often, this is just chance... when breeding, a hybridizer selects parents with desirable characteristics (form, size, color). The ploidy is likely unknown. (Not easy to determine, not a routine test) If something just won't breed, triploid or other odd polyploid genetics can be suspected as a factor.

In addition to what Roberta said, many (most?) orchids that are polyploid or are suspected polyploid (i.e. treated with chemicals to become polyploid) are usual labeled as such by the breeder since they can charge more money for such genetics (or suspected genetics)!