Is the Torque Dog just pressure? I'm not very familiar with Bully Dog products. If it is, yes, you can use it for pressure and just leave the rp setting on the Smarty on 1, which is stock. That way you will not be doubling up on pressure.
You may like the Smarty's pressure better than the TD's, I like the EZ's pressure better than Smarty's, it is more consistant, Smarty's pressure feature was eratic on my truck, so I opted to use my EZ.
If the TD also does timing/duration, you want to be careful stacking with Smarty, use the least amount of timing with the Smarty to start, just to see where it's at, and then you can increase until you find the sweet spot. That's whats so cool about the Smarty, there are numerous parameters you can play with, until you get it right. What works on someone else's truck, may not be the best for yours, play with it, and write down the outcome, thats what I do because I can never remember, the notes come in very handy.
Have fun! Jess