You can get a test kit that has one each of 125, 150, and 180 grain. Personally I like the 210 grain. Nice solid blade with no vents. My wife will be shooting the 100 grain version at plains game out of her mechanical contraption.
But I'm also an open minded short guy that shoots a Morrison...I have grizzly 160s and 125s, woodsmans, and Magnus 135s that I glue on to various size adapters for my carbon shafts.
The heaviest I can get my arrows with a 210 Silver Flame is 630 grains without adding weight inside the arrow. I can get to 670-680 grains with the grizzly 160s and the Magnus 135s. I agree that the Silver Flames are great, well made, super-scary sharp out of the box ( I've bought my share from Marcus, Herb and Vince). Even Dr. Ashby gives the Silver Flames the #1 rating for it's class...screw in replaceable blade broadhead.
But I can also take a grizz 160 and turn it into a 260 to 285 grain screw in, sharpen it and modify it as directed by the good Doctor, and come up with a deadly sharp broadhead. I can also turn a Magnus 135 into a 260 grain screw in and have a deadly sharp broadhead.
Definately more than one way to skin this cat and with my shaft choice the heavier FOC I can get with either the grizz or the magnus equals better arrow flight and deeper penetration than with the lighter variant of my arrows.