>The simulation has to be 'good enough' to make a thinking person (win the lottery); my mind has to be only smart enough to think of multiple universes but not perceive the obvious simulation artifacts; I have to be written (as a simulation myself) to be capable of accepting multiple universes.

But how could we possibly know what are simulation artifacts without knowledge of the rules of the outside universe? Paraphrasing an old SMBC comic, we live in a universe with a maximum speed, a minimum temperature, and a rule that position and momentum are only knowable to certain tolerances. If I were writing a universe simulator, heck yeah forced locality of side effects within the light cone makes the simulation and memory structures much more manageable.

Is that just the natural state of how things exist? Or are they constraints from simulation optimization within a parent universe where objects move infinite distances along 20 spatial dimensions as fast as they'd like? Depending on the rules outside, maybe our light speed limitations don't even help with simulation optimization and they just put that rule in here for fun to mess with us.

I just don't see how we have any grounds for talking about the odds of being a simulation based on absolutely no information. Best case we can say "If I make these assumptions about the parent universe I can draw X conclusions," but that doesn't mean much.