Dragnet format is GSE (graduate Standardised Exams). its an in-house format, so you'd never get practice questions for them, except those that Dragnet uploads at
www.faceoftesting.com/sample. It comprises three stages of about 17 minutes each. Verbal reasoning, quantitative and abstract. You have to be faster in the Verbal reasoning, as its always the most tasking. The maths and Abstract are pretty easy. however, prepare by reading and understanding GMAT comprehension passages, as well as their Abract reasoning, cos you'd see very weird shape patterns. I wish you all the best.
Just Curious!!! for those who got the invite, what class of degree do you have? Did any Engineer with 2.1 get the invite?