I actually agree with most of Smith Crazies post above except that I don't use either SR 4756, or have access to any WC820. I generally have had excellent results with HS-6 for top end standard loads in .38, as well as .38 +p loads. I also have had good luck with Unique for standard loads in the .38.
These loads are all within industry standards according to the manuals I got them from, and have given no problems in any of my guns what-so-ever. I have no control over your loading practices, shooting conditions, or the gun you may choose to shoot them in. Please keep this in mind.
125 gr. JHP- 5.5- 5.8 gr HP-38/231 std primer
125 gr. JHP- 6-6.5 gr Unique std primer
125 gr. JHP-6.5-7.5 gr HS-6 std primer
125 gr. JHP-7.5-8.5 gr HS-6 std primer = +P load
For the .357 I have had pretty good luck with H-110/296, 2400, AA#9, and yes, Blue Dot. HS-6 makes for really nice mid-range loads in a lot of calibers, from .357 up to and including my .475 Linebaugh. I know Blue Dot isn't recommended for the 125 gr JHP any more, but I never had any trouble with it.
I won't list any loads for the .357, due to the huge number of different guns available, and in different material types. I have only had experience with the .357 in all steel guns, and don't plan on changing that. I use loads that are available from the well known major bullet, and powder companies. I start below max, usually in the middle of the loads listed, and work up to what they recommend, or until I see signs that I am getting very near what the particular gun I'm shooting them in will take without probelms arising like sticky extraction, or a sudden jump in velocity that is out of line with what the way they have been tracking acroos the screens.
I will say that when working with H-110/296, be careful to follow the manuals exactly! They don't work well in loads that are reduced even slightly. You could end up with delayed ignition, hang fires, or dangerous pressure spikes.
I hope that is of some help to you.