I've never grown GD, but I grew Chadwick Cherry last year and whoever labeled it as 36-42" obviously never grew one. It was a HUGE plant, easily 8-10' by fall. It grew up over the top of a 6' privacy fence and down the other side, not to mention over the tops of all the other tomato varieties planted nearby. Per my 2012 notes, I picked my first ripe CC on July 15 following a May 14 transplant, so similar to what you're getting this year.

Here's an old discussion where the dtm of Chadwick Cherry comes up as 70-75 days. Gardener's delight is coincedentally mentioned but not its dtm. Cheers!

Here is a link that might be useful: Old discussion