I shot ST's last year. Shot one doe and hit a little high but the exit was just behind her opposite arm pit. She didn't leave much of a blood trail at all.
One poor shot, does not a statistical sample make.
I've used Thunderheads in the past, and they are a very good head. I've also shot a fair pile of deer with ST's. Not sure what the blood trail differences are, but a high shot with a 2" cut mechanical leaves a pretty poor blood trail in my experience, so I have a hard time imagining that the small difference between Slicks and Thunderheads would make.
Over the past several years, I've settled on Slicks, Nitrons, and Muzzy's, all 1"-1 1/16" cut for fixed blade BH's. In every case, they have been just as lethal as the larger replaceable blade and cut on contact heads I've used since 1967 when I started bowhunting. Shot placement kills deer quickly, not 1 1/4" or even 2" cut diameters. Shot placement also determines the amount of leakage after the shot, if you need that to find them afterwords. These days I use fixed blade heads from my lighter bows only, for deer. The lower drag from the smaller diameter cut is better for penetration. For my heavier bows, I shoot Steelheads and Spitfires as they are less prone to wind drift, and shooter error when you get cold and stiff. They also seem more stable at 290-300fps.
If you stay with a fixed blade for hunting, legacy Slick Tricks may be the best BH available today.