Some of my first photos with A6300

Craig, I first bought a wet diopter cause my camera was a compact and it was the only way to gain some magnification.

As I haver learned from theory, magnification is dependant of lens focal length and focusing distance. There are several ways to increase magnification, ones increasing focal length and ones reducing focusing distance. In the first group you have the extensions tubes and teleconverters. In the second, diopters (also named close-up lens)

You have use TC. The downside of a TC is that you loose aperture in the same proportion as you increase magnification.  So less light passes thru. Your 105mm f/2.8 with a 1.4 TC becomes a 147mm f/3.9 (rounded 150 mm f/4). That I think is clear for you.

Now, diopters reduce the minimum focusing distance of a lens. But they impose also a maximum focusing distance that is the Focal length of the diopter.   For instance with my +6 diopter is Focal length 165 mm (in my case, INON UCL-165M67 this FL is considered UW)  My focusing range goes from max 165mm from the lens to some let' s say 80 mm (this minimum  I think has to be with the lens behind the diopter but not sure).

So you have a small range to place the camera and be able to focus. But in the positive side there is practically no lost light and good diopter are even achromatic to reduce CA.

They are more effective with lens of long focal length than those with short. So, with my zoom lens I try always to use it in 50mm. Theoretically, the native magnification of aprox 0.22x of this lens becomes about 0.60x with my +6 diopter.

Extensions tubes is something I've been thinking about as an alternative

Regards