I currently play (standard bar-band cover stuff) all over San Diego, CA. Mostly smaller bars (say, up to about 120 people capacity). I usually run a GK MB150E. 100 watts, 1x12. Sometimes I'll run the extension 1x12 which brings the output up to 150w. I also have my "big" rig, which is an Alembic F1-X preamp into a QSC PLX1600 power amp (500w per side at 4 ohms) driving two Eden 2x10 (one XLT, one XST) boxes. I have never needed anything more than that, regardless of with whom (loud, full-stack wielding chunka-chunka guitarists or jazzy 335 guys running into a Princeton) or where I've played...indoors or out. If the rig I brought isn't enough to fill the house, the PA certainly is, and I run a line into that.
So, to answer the OPs original question, in my over 30 years of experience, 200-400 watts should be plenty to drive a 410 (an Eden XLT can handle 800, I think?), but "more is better", giving you headroom for a louder signal that retains clarity. If you have the resources to acquire an Eden 410 and a WT800, that's a fine set of gear by anyone's standards, and should provide more than adequate power.
I'm constantly amazed by the quoting of specifications and absolute statements along the lines of "that won't work" or "you can't do that". I admit, I've never met a 1x15 that I loved, but plenty of people have used 1x15 + 4x10 setups successfully.