I have not worked with any load lighter than a 148 grain wadcutter in .38, but the powderpuff .45 ACPs previously allowed in IDPA worked very well with Hodgdon Clays powder. And a friend loads 125 grain cast bullets and light loads of Clays for CAS with .38s.
Note: That is Clays, not International Clays, or Universal Clays, just plain Clays. There is a difference.
Clays is a flake powder but meters fairly well.
Caution: Watch out for stuck bullets. Copper-on-steel friction is higher than with greasy lead and too light a load won't clear the barrel. I have not had any trouble with sub-700 fps loads with .45 FMJ in my old S&W M25 but a friend has stuck several bullets with the same recipe in his 625.
Better you should load lead bullets. If you worry about fouling try moly coated. Precision was good but they no longer make .38s. I have some Bear Creek to try next.