you are having lots of problems with this floor.
have you considered glueing it rather than shooting it?

20 bucks says the staples will be worse...I prefer cleats over staples hands down..Those staples will fold right over, I guarantee it ...If that floor is that hard,what makes you think going with a thinner fastener will work?

Good luck on the install. Hope it works out for you.
Before we finally gave up on bamboo as a floor covering, we had the best success using a Primatech Q550 nailer in conjuction with 1 1/2 inch by 18 gauge cleats.

The install was done two years ago. I did it with 16 guage staples on the main floor area, and glued with construction glue on the stair treads.

Results:
- the floor looks great, and are withstanding a tremendous beating from our Black Lab without damage.
- the staples worked better than the cleats because the "arms" are thinner than the cleat, and caused less, but not zero splitting of tongues.
- I did have some trouble with the staples getting squashed and jamming the nailer because the "wood" was so hard. 1 in 30 maybe?
- I think some staples didn't sink as deep as they should have, so sometimes the next row wasn't as tight as it should have been - and in the dry season, I get some pretty good gaps between boards, although I'm the only one who seems to notice.
- the glued boards on the stair treads are tighter.

If I were to do it again, I would either glue, or use a click system.