In our 3 parameter model of where are the grabby aliens in space and time, each parameter can be estimated using existing data: our current date, the dates of major events in Earth history, and the fact that we don’t see aliens clearly visible in our sky.

What if we allow conditional grabbiness, so that if they see a planet with say life, or advanced life they let it alone? It seems like the model still applies, but the assumption is that the required arrival time is not 13.8gy but 10 or 13 gy. If we are still typical but the hard steps are passed early, leaving only minor steps, then it seems like the model has the same shape but the time when half of the universe is occupied is pushed back significantly, decreasing the distance to the nearest grabby civ.

Very happy to see that v2 of your paper has new section 16 on SETI. I think it's beyond your paper to ask exactly what signal to look for. But I assume given the grabby model, that waste heat would be the natural target. So along the lines Jason Wright suggests. https://sites.psu.edu/astro...

What makes you so sure that GC expansion must be spherical? Without analysis or evidence, this seems like an error of yours. Galaxies are flat, and resource dispersion (stars) similarly so.

What if we allow conditional grabbiness, so that if they see a planet with say life, or advanced life they let it alone? It seems like the model still applies, but the assumption is that the required arrival time is not 13.8gy but 10 or 13 gy. If we are still typical but the hard steps are passed early, leaving only minor steps, then it seems like the model has the same shape but the time when half of the universe is occupied is pushed back significantly, decreasing the distance to the nearest grabby civ.

galaxies are evenly distributed in space, the shape of individual galaxies doesn't matter

Very happy to see that v2 of your paper has new section 16 on SETI. I think it's beyond your paper to ask exactly what signal to look for. But I assume given the grabby model, that waste heat would be the natural target. So along the lines Jason Wright suggests. https://sites.psu.edu/astro...

What makes you so sure that GC expansion must be spherical? Without analysis or evidence, this seems like an error of yours. Galaxies are flat, and resource dispersion (stars) similarly so.