You're braver than I am or ever was. Knitted material tends to sag when wet so hopefully that fixation will help with that. If you can buy online here's a few sites.
http://yarn.com/webs/0/0/0/0-1001-12...FSosagod9XY2Mw
http://www.onefineyarn.com/Merchant2...y_Code=CAS_FIX