Hi,
Sounds like a great idea, and I like the ones in the link you shared.
I would be wanting them in the middle of the keel, which is a good 1.2 to 1.5 aft of the mast on a 29.
I don't think the 29 falls on her nose (mine certainly doesn't but she also doesn't have a mast up yet), so I don't think you need to worry about holding her bow up.
Kind regards,
Greg.
C29 - Sea Dragon