For the OP, I think most people would want to know what was the shot placement for the bucks that didn't have a blood trail and what bullets you used. Not saying you're doing something wrong but differences in those 2 on different animals could explain a lot.

When the OP mentioned Brush busting ballistics, I got the impression he was talking about something for short range that gets him as close to bang flop as he can, not something that's going to go through brush without deflection. I could be wrong and only the OP can say what he meant for sure.

As for the different definitions of still hunting, they can be a little tricky. Spot and stalk implies one is spotting a buck from a vantage point and then stalking it. If you don't have that vantage point to glass until you find a buck to stalk, then it's not quite spot and stalk. Still hunting can sound like a misnamed style of hunting but if you're doing it right, it does involve a lot of standing still, preferably in some kind of cover. It does involve some degree of stalking although it depends on how close you can get or want to shoot. I guess for me, still hunting could also be described as take a few steps slowly, stop, do a lot of looking and then glassing and sometimes just wait for things to settle down. The rinse, repeat a lot more times. It's effective and a lot of fun. I've tried just sitting in a ground blind and that is extremely hard to do. I like moving and exploring the country a lot more.