Hey Carlos,
I was glad when I read your last post and found you getting your loads down. To me, you started out getting all wrapped around the axle from starting at the wrong place.
In the beginning, you were talking about loading your rounds at the upper end of the loading spectrum without any mention of working up to these loads. You were concerned about the specific speed and pressure of the loads. Instead of worrying about speed and pressure of high end loads, start loading at, or, better yet, lower than starting loads, and then work up from there until you find what you want. Along the way up the loading spectrum, you will look for signs of pressure when they begin rather than when they are already too excessive. Chances are, you will find a satisfactorily accurate load long before you are at some bone crushing load that beats the heck out of you and your rifle.
Remember, there is no law of reloading that says you have to shoot the hottest fire breathing loads to be a real man. Actually there is an old reloading standard that says you should start low and work your way up, and that is the best practice.
WC-846 is a great powder and a great value today. In addition to 308 and 243 use, I also use it in my Marlin 1895 Cowboy 45-70. Having said that, I am not suggesting that it is good for everything you own. However, it is a fairly flexible powder that you might try in a variety of calibers and find it works well in some of them.
WC-846 is often equated with BL-C(2) and H380 in burn rate, but you can also consider published data for Win 748 and IMR 4064 powders if you start out low and work your way up.
Remember, if you start low and work your way up, you are a whole lot less likely to get into trouble in your reloading activities. I would also suggest that you get a Lyman reloading manual rather than relying on the Lee manual. Lee does not do any test firing, and all his load data is simply reprinted from data supplied by the powder manufacturers. The Lyman manual is a far greater wealth of information, and it is what I would recommend as a "first" manual to buy. There are other good manuals to be sure, but the Lyman has been the mainstay for many folks for many generations - not just years.
If you start low, work your way up to a good load, and find no signs of pressure along the way, you don't have to worry about how many CUPs or PSI your load is producing. As long as it is working properly in your rifle, that is the main thing.
One more thing to consider, if you have a good working load that is safe in your rifle, do not assume it will be a safe or good working load in another rifle. Once again, you have to start low and work up for each rifle and each load. If you have a good load for your rifle and then decide you want to change to a different bullet, there are some new things to consider. If the bullet is a different weight, you should start low again and work your way up. If the bullet is the same weight but simply a different nose shape, you are not likely to have much of a problem using the same powder charge - unless your load is already a hot load in your rifle. The hotter you load, the less room there is for any variation in the recipe. If your loads are in the medium range, there is a lot more margin of safety which allows you to make safe substitutions of components if thought through before doing it.
Surplus powders are good. You just need to follow sound reloading practices of working up loads rather than starting at high end load and seeing if anything is wrong.
Best wishes,
Dave Wile