Try taking it out a little lower (135-138) and tenting it under foil for 5-6 minutes before cutting. Residual cooking will carry over that temp to 145, which is about the max temp I'd want for tender.
Brining will change your life. Best way to do it (so you avoid an overly salty final product) is a technique called 'equilibrium brining'. Get the container you will hold the pork in while it brines on a scale and zero the scale (tare). Add the pork and just enough water to cover. Check that combined weight, measure between 1% and 2% of the water/pork weight in salt. Remove the pork, add the salt to the water and stir to dissolve. Return the pork to the brine, close/seal, then pop it in the fridge for at least 12 hours (24 would be ideal). You can leave that tender in the brine for days on end and it will never rise above the salinity of the solution. (This works for firmer-fleshed and fatty fish, too. But you only need about 20-30 minutes to hit equilibrium.)
It takes longer, but you end up with a uniform amount of brine throughout the product instead of heavily brined outer layer and barely brined interior with a middle bit that's more or less okay. (Hence the term 'equilibrium brining')