Current Alliant data shows 3.1 gr. of Bullseye as max with the Speer 148 HBWC.
That said, my Lyman 46th edition shows 3.0 to 4.1 gr. as the range for Bullseye with that bullet.
My current favorite load for 38 Special is 3.4 gr. Bullseye under a 148 gr. DEWC seated to an O.A.L. of 1.420". This shoots very well in everything I've tried it in and certainly seems mild enough. My K-38 loves it.