Don't put in the sump, that's a very vulnerable place to have a sensor that could easily get ripped off over a bump or by a rock and result in you losing all of your oil!
maybe still in the sump but not at the bottom end of it!
Yeah you could take the sump off and weld on a fitting for it, or if you check in my garage I've put mine in the oil filter housing which seems to get a good reading (same as a sandwich plate there would). Others have also fitted them on a feed off of the standard pressure switch so there are a few options.