This can get into a pissing contest disagreement, but here is how I see it. The spotting drill needs to have a larger included angle "cone" than the drill that will follow if it is to be a centering aid. If you are using a standard 118 degree drill then you should use a 120 degree spotting drill, if using a 135 degree drill, then use a 140 degree spotting drill. Make the starting hole a little larger than the chisel point of the drill. That way the drill is actually centered by the larger angle starting cone. If you use a spotting drill with a smaller angle, the drill's cutting edges will catch on the corners of the cone and the drill will walk. If you drill the spotting hole larger than the drill bit, then the outside edges of the drill will kinda wanta center in the smaller angle cone, but the outer cutting edges will still tend to grab and the drill will still tend to walk in the smaller angle hole.
Now, if you check out the sale catalogs of Enco, MSC, Travers, etc., you will find that about all they put on sale are 90 degree spotting drills. Is everyone using drills with angles less than 90 degrees? I don't think so. 120 and 140 degree spotting drills are certainly available, but they are much harder to find, and you probably won't find any on sale.
Me? All I have on hand are a few 90 degree spotting drills, so I do not walk my talk. Instead, I just use the 90 degree spotter, drill slightly larger than the chisel point of the following drill, and start the second drill gently and carefully. That seems to usually work OK. More and more, I just use a stub length drill bit with a split point and just drill the damn hole, starting gently to get it established on the mark. That works well. The stub drills are stiff, and the split point drills do not walk, those drills require less pressure to cut, and it eliminates changing out drills constantly. With a stub length, split point drill you do not even need a center punch mark for drilling with a drill press or on the mill if the work is flat and perpendicular to the drill. Just start the hole by pecking gently.
There are arguments for other approaches as well, listen carefully, think about it, and decide for yourself.