I have filled my share of holes in travertine floor tiles, and I usually use a 2 part filler from Tenax.  I looked at a large area yesterday that was a less expensive grade of travertine and there were holes everywhere.  I can't see using a 2 part without taking forever because of the pot life of the 2 part filler.  Traverfill (or unsanded grout) is an alternative but the owner of this rental wants a medium shine on the floor.  With traverfill I can use a grout float and get the hole filling done faster but I am worrying how the non-shiny fills will look compared to the shiny stone.  Are there any alternatives that will fill the holes quickly and still blend in with rest of the floor?  Thanks in advance for your suggestions.  Sorry, no photos.