Fillers
The problem with fillers that are *not* epoxy is that most "shrink" with time or worse (bondo for example, especially glazing putty), will absorb moisture. Neither are good for laminates.
If you really want to fill pinholes and do it the easiest way. There are 2 approaches.
a) take a dry mix of micro and epoxy and "trowel" it on with a wide sheetrock mud blade, using your hand with all the fingers on the back and your thumbs on the front, at a 20-30 degree angle and with lots of pressure to squeeze out the airbubbles. When cured, sand to contour
b) if already really smooth, but only need to fill a few weave holes or pin holes, use regular epoxy and put it on with a squeegy, pulling most of it off. The epoxy will fill the pin holes, where a putty will just fill over them. It might take a couple of passes to get the pin holes all filled, but it's pretty easy with taking almost all the epoxy off when you do it.
For more info, google chapter 25 of the cozy, varieze, etc manuals and peoples reponses. There are some very good, and pretty easy ways to finish FG with one pass if done right.
I should know, I'm usually up to my armpits in it every day