Modern hybrids have a complex gene pool developed over many generations of hand pollination.
You can be sure that a double x double and an anemone x double will give predominantly doubles, a single x double may give a double but often anemone and singles. The % of full doubles and anemone forms is dictAted by the double used to make the cross.
When crossing singles with doubles it can take 2-3 generations to achieve a full double, back crossing of an anemone with the double will give the best chance of doubles. Some doubles can have low fertility as well as poor pollen production, this I put down to line breeding.
Colour is more difficult to predict, especially when the parent colours are very different. Spotting is said to be dominant but again it depends upon the parents used.
My suggestion is that you make both crosses and see what the outcome is, that is the excitement of creating your own crosses as you will end up with plants that are unique to you. Reverse crosses are also a way of understanding the dominant genes of the parents.
You should get up to 30 seeds per cross, if you have space than you can grow on all seedlings to flowering, this will give you the ultimate indication of which of the parents is the dominate parent, I have never had the space to do this. I select seedlings that show early vigour and only grow these on to flowering.
Be warned 'breeding' hellebores can become an addictive past time, it has taken me nearly 3+ decades to kick the habit. Good luck, I am sure that you will find the process both rewarding and frustrating.