I don't know that I would name myself a builder if I didn't know how to build. And I am no engine builder, but basically, to over simplify as best I can understand it, changing the stroke is a way of increasing displacement without increasing bore size because the piston moves further, but you gotta have other changes too.
There's no real advantage to just slapping a different length rod in, you'll just ruin it, you need the right length for what you're doing. Changing the rod length, from what I understand, requires also changing the case and maybe flywheels. You can't just willy nilly change the rod length. Unless you're ordering a 113" engine and trying to decide between a 113" that's a stroker or a 113" that's a big bore. So are you building an engine, or building a bike around a particular engine?
It's actually more complicated than that.
Also, displacement (like 113 ci for example) is determined by the bore size multiplied by the stroke length... well, technically, it's π x (½ x bore)² x stroke x number of cylinders
. For it to be 113, for a given bore size, it needs a specific length rod. So if you're building a specific size, you need a specific length rod for a specific bore size.
Quick Google search... https://en.wikipedia.org/wiki/Stroker_kit
A stroker kit is an aftermarket assembly that increases the displacement of a reciprocating engine by increasing the travel of the piston (that is, the piston moves farther up and/or down in the cylinder). This is done by replacing the crankshaft with one where the crank pin is moved farther away from the center of the axis of rotation of the crankshaft. While this increases displacement and torque it can potentially lower the limit to which the motor can rev safely compared to the stock configuration.