A small point, but to me, SS and pensions are not an allocation or asset, but a subtraction from spending. I'm overly conservative, ignoring both of these, and my way to deal with a potential 50% drop in the market is to do two things. I double the amount needed to sustain my spending in retirement and as mentioned, I ignore SS and my small pension. For any SS consideration, realize that in about 2034, the trust fund goes to zero and payments will be only what's coming in, which will be something like 75%, so a 25% drop for those taking payments. I also do set my AA at 50/50. I also tend to favor large cap and for international, only developed.
I did say I was very conservative, right? At 52 times spending in investments right now, both DW and I are working full time. Why? Because DW won't let me retire yet.