The World Models 46 Ultimate takes a 2.25" spinner. At least, that's what's on mine. The one in the picture looks very much like a WM.

No need for 4-40 size at all. Matter of fact, they'd be unnecessarily heavy. Not a lot heavier, but absolutely not needed. In theory, all the weight added to any surface increases the probability of flutter depending on how far aft from the hingeline and the amount.

Here is a picture of the rigging done on my Skybolt. You can see that only the top part of the provided aileron horns are used. The bottoms of the horns are removed, and just the working part of the horn is epoxied into the slot cut into the aileron. Simple, and almost no weight needed. My pushrods are always made with a solder clevis on one end and a screw clevis on the other. I like clevis connections as they cause no twisting torques and like to have one of them rigid, which solder does. No excess solder of course. Same rigging is done on the Ultimate but the picture is better of the Skybolt. Those rods are so short and the air loads so light there is no problem with flexing.