I am about to say something very controversial and will likely get me banned by Admin but I will say it anyways.
Powder choice is far less important for accuracy than the proper bullet weight, shape and speed based on the rifling twist and condition. For example, I am working up loads for my Spanish Mauser. if I can achieve 2550 fps with a 175 gr Spitzer, the powder used to get there is much less important. The accuracy remains the same regardless of powder.
for tbe most part i dont think powder matters as long as its a safe burn rate and with in the range of safe chamber pressures.
When your splitting hairs burn rate can play a part.
As far as what is the ideal , that shows on your target.
i will give you some examples.
i use H4895 for almost every rifle load i shoot from 223-7.7 jap its versatile and will produce ammo that will only be limited by me.
Get deep into technical stuff like barrel harmonics and when the powder stops pushing on the bullet.
Are you trying for max velocity?
Some powders will reach dangerous chamber pressures before they reach a desired velocity.
Varget is another powder I use and it proves to be well with in my equipment and skills to deliver better than I can on a regular basis.
But i find varget to have a smaller window of forgiving charge weight than H4895.
i can toss 44-47 grains into a 30-06 case under a 168 grain bullet and load them randomly and still hold the 10 ring.
Its all good
Right now common powders are OOS. There are other powders that are in stock right now. All though a bit more expensive.
Im cheap and 90% of my reloading is for fun plinking for pennies , i load for cmp matches and NRA service rifle so im not looking for sub 1/2moa for the most part. i do have a AR i intended to shoot 600 prone with that i was looking to get at least 1/2 moa just not a lot of time for that recently
Fritz - you will have to try harder to get banned , lol
Or go to one of the touchy forums