Hi Martin good idea to heavily plant your tank from the get go for sure!Benefits are that you will be creating a healthy tank from the start,with a good plant mass you will have less of a chance of having a problem with algae which is a right pain and a common problem in the new tank.Important to have enough fast growing plants to start with eg.Hygrophila polysperma,Ludwiga repens,Hydrocotyle leucocephala etc.These plants can be removed and replaced with other more desired plants if wished when the aquarium has become established.The fast growers strip the nutrients from the water giving algae less chance and also create a better environment for fish/inverts.All in all you can say it helps to plant heavily from the start then it's down to other factors(Co2,flow,light,etc...).Cheers mark