I deleted a couple of posts questioning the safety of loading below book data. Not because of that, but because of the other personal content in the posts. Questioning the safety of something is never a bad thing. We should always be cautious in our hobby.
It's was a good idea to ask here about loads not in the books, as many people have a lot of experience with them. Yes, beginners should definitely stay withing the parameters of proven load data, but for as long as handloading has existed handloaders have experimented. We all do this at our own risk when we do of course, and the more experience one has the less likely they are to get into trouble, but it can still happen.
People have been loading the .38 Spl to very light levels forever. It can be done safely, but it can get you into trouble as well. Certain powders are more suitable for it than others. If we are willing to point the muzzle up before every shot to get the powder against the primer, even more loads are safe, but I prefer loads that will get the bullet out of the barrel 100% of the time regardless of powder position.
Bullseye has been used for light .38 Spl loads for a very long time, just be careful with light loads and make sure the bullet always exits the barrel before firing another shot. I would advise against jacketed bullets for this, plated can be iffy, though doable, but lead is the safest way to go because it has the least friction. Soft lead HBWCs or soft lead 125 Gr or lighter lead bullets are best suited.