A "proper" turkey load might be loaded a bit hotter & have a maximum payload of a given shot size - = max dram/max load.
A bud uses Winchester's 1-7/8 oz of #4s at max dram & does very well. At around ~$14/25, it's cheaper than the touted "turkey loads." Have a few boxes myself ....
A turkey load is what kills turkeys consistently - likely a statement about the hunter rather than the load, although a tight patterning load (for your SG & choke) is better than not.
& having never used nothing smaller than #4s for the big birds, I can attest that they (#4s) do shoot through feathers jolly well enough.
I would stay away from anything called "turkey load" for home defense as that's not what they're made for (i.e. a single shot/very tight pattern at fairly decent distances). HD is close-in, quick & possibly multiple shots.
'Sides, I know of no place that allows #1 buck for turkeys (CO limits to #2/T shot sizes) ... betcha you either misread the ad of Cabela's misprinted.