I was finally able to score some 7mm pills for my STW. I've had good luck with SSTs in other rifles. How would the 154 grain SSTs do on whitetails out of the STW?
I shot the 140g Nosler C/T bullet in my 7 STW at 3600 and never had a single problem killing deer. The 154 SST is kinda fragile and as long as your shots are 150 and further, I do not see you having a problem.
Know where the diaphragm is on the deer, aim for the diaphragm which is way far back from the shoulder. Diaphram shots usually end up with a DRT result.