Y2, In my above post, the comparison to loin and poultry was that they neither one require long cooks or low temps to make tender. I have cooked loins at higher (250 or above) temps but don't make a habit of it like I do with chicken or turkey.
Loin will be fine at lower temps with other stuff, the key is not over cooking.
I'm not a big fan of mops or sprays. Neither do much for the internal moisture of the finished product, they can add another layer of flavor, but no additional moisture. Even if the mop or spray is heated the effect to moisture content is only marginal, if applied at room temp they do nothing. In fact when considering that each time you open a cooker to spray or mop you're extending the cooking time which can lead to a drier finished product, spraying/mopping can be counter productive with respect to moisture content. If you're lookin' you ain't cookin'.
I'm not recommending that you abandon spraying or mopping altogether, just that you be aware that it is really about flavor (and appearance) and really has no postive effect on the moisture of the meat at the table.
Moist meat is achived (IMO) by 2 things, proper prep (brining/injecting and a good rub with proper sugar content to crust up in the latter half of the cook to help retain juices) and stopping the cooking process when the proper internal temp is reached.