This is a very interesting subject and it gets down to the details of who should spin and who should glide. The points i look for in an athlete who is going to be a glider today is an athlete with a good standing throw. This happens only one of 2 ways. 1. the athlete has what i call an golden arm which is very rare in throwers (Only seen an handful of these over the years) 2.or someone that is very tall and long levered and strong especially in the upper body. Big stands take a big CNS and this is why we don't see many now a days. In the 80's 20m stands were common place and the top level stands were over 70 feet. I personally have seen some of these.
This lost of the big standing throw has lead to the revolution of rotational throwers in the past 20 years. An excellent technical glider can only get about 7 feet on top of a standing throw on the average. The top men rotational style throwers today mostly throw stands right around 60 and many of them less then that. Some of these men have great weight room numbers that should indicate bigger standing throws but it just doesn't happen today without the peds because that is what drove the CNS to make all those large standing throws. The stand is a partial movement of the full throw and to create big distances the body has to create horsepower at a much faster rate.
Ryan's numbers on the standing throws he has seen is the same Dan Taylor and Cory Martin have told me they have seen also.