The guarantee cannot be beaten, because they basically go as high as possible with their bets to make sure that they do get a win, eventually.
I actually have the system, but have never bothered to look into it, but I do know that to go 10 races without a winner is not impossible.
If you played the winning Factor and had 10 straight losses, I reckon your next bet would be about 5 grand!
I didn't bother looking any further.

So far as staking plans go, what if you base your staking on the results of a full meeting?
EG. Week 1 - Sat Belmont - You are $4 down, having placed 8 x $1 bets.
Week 2 - Sat Belmont - Now play 8 x $2 bets.
We are only trying to recover a $4 loss, and if we have a good day, we could be way in front.
If are play is positive, drop back down to the $1 bets for week 3.
If not move up to $3 bets.

Do you reckon this is still doomed?