Size 12 Track Attack attacks on the bottom and Size 10 Tracker IIs on top.
I also have a pair of size 8 Track Attack shorts (on top) to compare to the Tracker IIs. Unfortunately, I don't have a pair of size 10 Track Attacks so I can't do a straight comparison.
Waistband of the size 8 Track Attacks (left) compared to the size 10 Tracker IIs.
Size 10 Groovy Run Shorts in Pop Plaid Multi compared to size 10 Tracker IIs. This photo is a bit deceiving and makes the Groovy Runs look like they run a lot bigger than the Tracker IIs, particularly the photo of the front sides. The shorter length and more generous leg opening of the Tracker IIs actually make the fit a bit looser, in my opinion. Both these shorts are cut for more muscular legs but where your carry your weight, will dictate which you prefer. On a nitpicky level, I prefer having the zipper pocket in the middle of my back on the Groovy Runs but I do like the more generous cut on the leg opening of the Tracker IIs.
Comparison of the leg openings on the Groovy Runs (top) and Tracker IIs (bottom).
Final comparison, size 10 Groovy Run shorts on top of Size 12 Groovy Runs.