No worries! Go ahead ask. This has been my favorite subject for decades and no one else seems interested to discuss it (not even my wife ) Not until they want boilers, tanks and radiators installed. I’m no plumber but I’ve done several intallations. I never got paid for it. I learned a lot however - I guess that’s payment enough.
Boilers are unfortunately rapidly replaced with heatpumps these days. People are drilling 200 m deep holes in there gardens or plowing down hoses creating permafrost until Juli and don’t worry about electric supply or a January compressor beakdown at all. We’ll see.
No, there is no grate at all. Logs lie down on a ceramic flat floor above the combustion tunnel parallell with the tunnel. There is really no need for that floor. There will be plenty of ash on it. Only reason is to create a void for secondary air plumbing. Floor actually rests on that plumbing. (I think pipes could just as well have been buried in the ash). Air will be somewhat preheated and enters into the restriction between tunnel and floor.
Ash down the restriction will all be blown back into the dropbox under the heatex tubes. If not, you can always push it back through the small hatch I was filming. Dropbox has a door on the side for cleaning out.