This past spring I had everything off the boat for painting so I did just this, except with the regular epoxy mixing. I do admit that this Six10 looks good. I wonder if the tube and tip would be a little big and inaccurate and messy? What I did was use 5cc plastic irrigation syringes to fill my holes and I found it worked great.
I quickly realized that you can't just blob some epoxy down the hole, it would leave voids that sometimes wouldn't rise to the surface. With the syringe I could fill the hole from the bottom up to eliminate voids. Granted I was using a home brew mix of resin and microfibers and I tend to mix it fairly thick. Even with my method, I had my wife follow me with toothpicks and give the mix a stir in the hole, and she did find a few voids I need to top-off after stirring.
Also, with the syringe, I could fill the hole exactly level with the deck, so no wiping up epoxy. Since I'm writing this much, might as well say that I pre-wet the hole edges with neat epoxy before filling.
So, back to the Six10 stuff, sounds like they have the formula down for viscosity, perhaps you could poke a small hole in the mixing tip that could accurately fill holes with. It would save time as long as it doesn't introduce a clean up mess for each hole.
I wouldn't flinch at the cost, with my method I mixed many small batches, and there was quite a bit wasted as the last of each batch went-off before I got it in the hole.