I believe that if you are comfortable with what you know then you will be comfortable and more relaxed then trying new stuff. I have always stuck with W748 in the 223 until I put 5 55gr V-Max's in the same hole using benchmark. If I feel frisky I will purchase a different powder like I did with CFE223. I have yet to find a great group with this powder but in spare time I will keep looking. You are doing just fine with what you have.
according to hodgdon there starting and Max loads for 55gr spr soft points only have a 1 grain difference starting at 25 and MAX at 26. use your book and be safe.
Let us know what the results are.
