I purchased the Mora 6" drill with 1/2 inch adaptor last year. Powered with a Dewalt 20 volt XR all last season. I carried 2 batteries with me and only needed them when drilling lots of holes (30+) and it was really cold. I drilled hundreds of holes with this setup and never had an issue even during late ice. I didn't pull out the gas auger (Strikemaster with 4 stroke honda) at all during the season.
The nice thing with this setup is that I could leave the drill in the back seat and grab it as I moved around the lake in the pickup. From the time I'd put the pickup iin park until I was fishing was less than a minute. Absolutely loved this setup for trolling new lakes.
I don't have the adaptor plate nor do I plan to get one. Just need to make sure you brace yourself a little so that it doesn't spin out. I'm no featherweight so this isn't a problem.
The 6" hole isn't an issue with most fish. Brought a 27" walleye and a 10+ pike through these holes with no problem. Only thing that sometimes happens with the smaller holes is fouling on the transducer. Didn't lose too many fish to this so not a deal breaker. When we fished in the house I'd drop the ducer down the dead stick hole if I had any concerns.
Several folks saw me on the ice with this setup and are moving towards it this year (assuming we get ice). I won't be going back to the "old way" anytime soon.