FTR, I think 51-52 probably is 'too old' to consider to. 68-69 looks interesting. arctic outbreak in late dec, lots of snow that winter
91-92 and 09-10 are duds here, warm and dry and probably more likely in our 'modern' climate unfortunately.
No such thing as bulletproof. It’s like throwing darts, you can miss without a blindfold, but you’re more likely to miss while blindfolded.
Believe it or not 1951/52 is in my analog pool, but in the lower weighted cluster, and definitely not the closest match to date.
Niño/descending E-shear, autumnal +IOD are the best dynamic fits and weighted double, as are non-modoki Niños lacking +PMM or very strong EPAC niños. Other mod/strong EPAC/CPAC niños or modoki niños lacking +PMM weighted normally, along with strong niños with +PMM. Other niños weighted 50%.