This can actually work. Dimebag Darrell had a masterclass where he said, “I don’t really know what I’m doing. I think it’s a pentatonic scale. At least that’s what I was told. But I don’t spend much time on learning scales, theory and all that other stuff.”
Then you have Marty Friedman say in a video, “I like to play a chord, let it ring out and find little notes that sound good in a sequence over that chord (plays a double harmonic minor). I mean I’m sure that’s a scale with a name, but I don’t know what it is. It sounds good.”
Slash, “I took a couple of private lessons then quit. Theory and all that other stuff came off more like math problems to me than music.”
So yes. This CAN be done. But I think ultimately you should have a good ear as to whether or not it actually sounds good. If your ear isn’t really adept and it sounds like a drunken carousel falling apart, then you should reconsider your approach.
Do you have any clips you can post of this “shredding”? Maybe we can help