You don't mention the size wire & boat.
However, I got the T-Ball rubber retaining plugs for my H260 as follows:
American Rigging Supply, Inc.
(772)336-3099 tel/fax
(772)359-1618 cell
www.americanriggingsupply.com
$2.00 each.
For 5/32 (4.0mm) wire Part No. N742.05
Note: it is tough getting them in and some minor trimming may be required but once you get them in they's stay. However I don't think the plugs are really the best solution. I've had the best luck by installing an eye/cable tie at each hole. In addition, I recently installed a mast hound for the furler and I'll add pictures to the H260 website soon.
More at:
http://h260.com/headstay/headstay.html
