Kind of like asking "What weight of oil should I use in My Harley", everyones got their favorite and they will give You what information they have on their experiences.
All good advice, in My opinion.
as stated, get familiar with the firearm and what weight and style of bullet makes the best match with the rifle, if You want to try a different bullet, reload that bullet of different weight/grains with different measure of the specified powder, until You find that "Sweet Spot" that everyone talks about.
Whichever bullet You are used to shooting will probably that Royal Bull down with one shot, if accurately placed into a vital area.
I have seen elk taken with a ,243 and a one shot kill at over five hundred yards, not a big bullet, just a load the shooter was comfortable with and, that worked well in His rifle then, placed in a vital area that He knew would bring that Royal six point right down.
Go getum.
A Nozler partition may work well in Your rifle too.