I'd go with the bandsaw idea, as I already did something similar. Drilling 4 or 5 feet into end grain logs will take some doing, even with a screwtipped shell auger and a 'gutbuster' drill, and you can bet your 'ol boots you will eventually lose a drill that won't come out from 3 feet deep due to wandering off line!
I think battery powered drills or an impact driver will take ages and hundreds of recharges. Tip; if
long-series drilling, keep the screw feed tip away from your feet, as the screw auger will pull it right through your foot before you can yell "OUCH!"
I sliced up an oak baulk to make a channel section, on a bandsaw, to hide a steel 'I' beam. Before
sawing, I drilled a few 3/8" holes sideways to the planned cuts, so that on reassembly, I could fit hickory splined wooden dowels [inboard faces] for relocation while clamping and glueing. The resultant join is invisible from close up, as the saw kerf is very narrow and the dowels keep everything aligned. You don't need a dead-straight saw line, and you don't need to cut absolutely
dead center- it will all match up pefectly on reassembly as long as you use the correct halves!
Which, of course, you will mark up
use a fence on the bandsaw, just run to a chalk line by eye - this avoids the dreaded 'twisting-undercut' caused by guiding on a fence. New or resharpened blade called for IMHO! In your case, I'd cut the feeder channel with a chainsaw tip along one half. I always use polyurethane glue on external work. 100% waterproof. It foams when dry and is easy to clean off the work. Wear gloves, as it permanently stains the skin. Adhesives don't take well on wet lumber, and in this case I would expose the cut faces to 'air' till they were relatively 'touch dry' to get a better key, if the lumber is wet.
And the best of luck!