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
.
I
never 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!