How would only 50% of the offspring be het Tremper and eclipse? All of the offspring would be het eclipse and Tremper. If you're referring to a 50% ratio then a lot of breeders are steering away from using percentages. Using a percentage is kind of like giving a guarantee of sorts. For instance if I had two het Trempers and said they were 50% het someone could assume that they would get an albino from the pairing when in reality it could be quite the opposite. They could quite possibly just get normals. Just my 2 cents
EDIT: You're completely right. Sorry. =/ Better go correct the other place I made that mistake.
Percentages, though. We're using Mendelian genetics, and I think everyone understands that the percentages provided are a probability and not a guarantee. Percentages (or ratios or fractions) are the only practical way to represent Mendelian genetics. It's like saying if you flip a coin, there is a 50% chance it will land on heads and 50% chance it will land on tails. Not a guarantee, but a probability.
Try using this website. Even though it hasnt been updated for awhile but very useful. At 1st it is a little confusing but once you get use to it, youll love it. Leopard Gecko Genetics Calculator