Actually, loin is typical, not tenderloin, and I'd recommend loin. Better size.
Get a boneless center-cut loin roast of about 4 lbs. They are usually well trimmed; trim off any remaining surface fat.
You can:
use a curing brine. I don't really use TQ for anything so consider this conversion somewhat experimental (but I think it will work well).
Pour 1 gal water in a pot on the stove and heat on high. While it's heating add 2 cloves of garlic, crushed, 2 T granulated onion, 1 bunch of sage*, one bunch of thyme*, 2 t white peppercorns, 2.25 c TQ, and .5 c white or light brown sugar and mix till the TQW and sugar have dissolved. Simmer 10 min over med/med-low heat then remove from the heat and allow to cool. Chill thoroughly in the fridge before use. (You can speed cooling by pouring the brine into a pot which you've already placed in a sink full of ice. Stir frequently.)
Place the loin (or loins; you could do two) in an appropriately sized flat container that's roomy enough so that it (or they) is not squashed at the sides or ends, then cover with the chilled brine, weighting the meat to keep it submerged, then cover the container and cure for 2-2.5 days at 36-40F. (Alternatively, place in doubled large Zip-locs, pour in the brine, seal well, then place in a container in the fridge to cure.)
Remove from the brine, rinse well in cold water, the dry as noted upthread.
-or-
you can dry cure:
Note the weight of the meat so that you can make necessary fractional adjustments to this:
Per pound of meat, mix together--
1 T TQ
1 t light brown sugar
1 t granulated onion
.5 t granulated garlic
.5 t dried thyme
.5 t rubbed sage
pinch ground white pepper
Mix thoroughly. Dry the loin. Place the loin on a sheetpan. Sprinkle the loin evenly all over with the mixture and rub it in. Use all the mixture. Place the loin in a Zip-loc, adding any spilled cure mix from the sheetpan to the bag. Press out the air and seal. Cure at 36-40F for 5 days, overhauling (flipping the bag) every 24 hours.
Rinse the loin well in cold water then soak in cold water for 1 hour, changing the water after the first 30 min. Dry then dry further as noted upthread.
Smoke as noted above, using Jay's suggestion. I like apple mixed with a little hickory but use what you wish.
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* if fresh is unavailable, sub 1/2 c dry, each, for the thyme and/or sage