The best tip I can offer,when it comes to betting on The Grand National..is don"t bother,and save yourself money..
It is nothing more than a Bookies windfall..they love it.
Most punters have no clue have what they are doing,being occasional betters,sucked in by the glamour and TV/Press hype.The size of the Field/number of Horses racing,and the gruelling,some say cruel,test of/accurate timing by Horse and Jockey(jumping of massive fences,positioning in race)..added to which,a Horse can be brought down,through no fault of Horse or Jockey,simply by colliding,or running into the path of another fallen Mount.
These factors,and many more,make it nigh on impossible to pick a winner in the Grand National...like I say,Jemisa,save your money..