You shouldnt need that size, but yes it will have more signal. If you use Alps thin lnb's you can get 13 + 16 + 19 and 28 all on a 1 metre dish. Very squashed but it works.
if i end up going for the spiderbox then i will definately be interested in doing this to get all of the gift channels.
one question though.
how do you know where to mount each lnb on the bracket? and at what angle and skew?
is it just trial and error until you get a good signal?
any help will be much apppreciated