I'm curious why you would run or reach when the squall hits. I would think you would want to beat into it so as to get past the heavy stuff on the leading edge quickly. You also present less area to the wind that way. Less tipping force
I can not reef on my boat. It is a C Scow. It is 20', weights only 600 lbs and has a large main sail. I also sailed E scows for 10 years which are 28', 1000 Lbs and have main and jib, no reefing. I found that I was best off sailing into the squall line, pinching up if needed to minimize tipping force.