I had something of the same problem, andt it may not have been as
severe as yours, but I installed an astragal
(http://www.aaaremotes.com/botsealweatf.html) (among other places)
stapling it to the underside of the wooden door. There are
recommendations to install it "backwards" (short lip outside) if the
driveway is higher than the inside of the garage, and I did that and it
worked OK. Gotta keep the sealing area clean, and it didn't keep the
water out during a truly major storm.
On the saddle idea: If the saddle doesn't flex enough, the door will
be in a position that is "open" relative to the bottom end of the
bottom panel (sectional garage door), and if the saddle is tall enough,
then the top of the door will be bowed in (it didn't close all the
way), and in cold winter climes, if your garage is under your house, a
lot of heat will go out the opening at the top. The garage door
astragals are extremely soft rubber and let the door come down far
enough so that the top section still can seal against the rubber at the
top.