I use the standard 4 supports, and since most of the weight is on the
keel, this hasn't appeared to put any undue stress on the hull. The
boat has been on the trailer for all of its 20+ years and has no
indents at the pads.
However, when I bought the boat there was significant blistering
under the 4 pads. Beware using house carpet as it traps too much
water underneath the pads during the long winter months and can lead
to water intrusion.
Other folks have suggested various better materials, from astro-turf
to ribbed rubber to help prevent trapping water against the hull.
Just something to be aware of...
--brendan
