Kevin, Was it full out sisal grass nice and dry.. Or is there possibilty that its sisal wool? Sisal wool is a very low pile berbered Wool that is woven to look like sisal but its constructed actuelly a nice woven piece of carpet and will hold up to some pretty intense cleaning.
If its true sisal then host would be our choice. If you have problems finding host, we still sell it out of our store, the pre-mist and
compound. While you can probably use a 175, the rotating action might be a bit aggressive for true sisal. You might even be better off using a hand brush if you feel it will distort at all.
We use to rent out the host machine as well but we couldn't justify 200 a month for the two machines.
However I did end up purchasing a newer style one off ebay about a year ago for rug cleaning, and prescrubbing. If it was something you wanted to try before making an investment in an actuel host machine or counter rotating brush machine, I'd be happy to lend you the machine for your first cleaning. Let me know if your interested.