225* would be closer to 15 hours. Most of my packers have run 18-20 hours in the 16lb range.
I would suggest no injection, and 225* for a good long stall to melt away the connective tissues to get good tender slice. Without injection, you don't have to worry about getting through the internal temp of 40-140* in 4 hrs. I try to foil @ 170*, 180* if I have more time...take to 185-190* and probe the flat for tenderness, 200*+ for pulled, warp in towels and rest at least 3 hours for a 10lbr.
If you want pulled beef from the point, separate the packer either pre-smoke or post smoke just prior to foiling after flat reaches finished slicing temps. Foil both cuts, return point to smoker/oven at 225* (while flat is resting in towel wrap) and take to 205* before towel wrap/resting.
Figure on 17-18 hours from start of smoke to slicing if taking the full packer to slicing temps, and longer for pulling temps of course. This will all be dependent on actual chamber/grate temps of your smoker (make sure it runs at what you set it to with a probe thermo, as some electrics can't pull much over 200-210* if it's cold weather).
I've separated the point/flat cuts (pre-smoke) and trimmed pretty lean if I want a good smoke reaction on both sides of both cuts, and there's still plenty of natural moisture with a water pan in the smoker.