I have shot plenty of smokeless in my Snider as have many others. True, you can't be as brainless as you can with blackpowder (where full cases are generally safe), but if you are competent to reload smokeless in 30/06 (where mistakes can be costly), you can reload smokless for the Snider.
I find that either a very few grains of a moderately fast pistol powder like Unique, or about 30.0 grs of a slow pistol powder like H4227 worked well for me.
Did you use a filled for the hollow space left in the case, or are the powders you're advocating reasonably resistant to positional sensitivity to not matter much?