John,
The link to your wood details will not work- is this correct ?
However the photographs on the Major Oak itself are very interesting.
If the saplings are in a 10 litre pot - I guess they may already be of a decent size, but they will need to be close to hand in your garden if possible to enable you to work on them.
If you are by the Oak shortly, pop into Greenwood Gardens. the home of Harry Tomlinson, who will have plenty of trees for you to look at and will offer advice. He is a widely travelled bonsai expert and author of several books. see
www.bonsai.co.uk
Meantime, the basic early needs are to keep well fed during the summer and to select the ones that have a good selection of low down branches that can be used in early development. You will get a better feel by looking at the many pictures held in the gallery section of this forum. This ultimately will depend on the finished size of your intended bonsai - but lets say you intend it to be 30 inches - the first branch should end up being a third up (general rule only) so at present you need to pick one with an interesting branch about 6-8 inches above ground. As the tree grows, this branch level will naturally become higher anyway.
It is then a case of feeding, trimming and then digging up - trimming the roots and re-planting every couple of years to help reduce down the size of the leaves, while at the same time building up as realistic a looking branch structure as possible. Then you could "style" it which is where the crossover of horticultural needs become linked to your artistic talents.
Eventually, on one of the dig ups you will be able to transplant into an oversized pot and then gradually reduce down the roots and pot size more as time goes on.
As I said in my first post - a lot to take in really - but do the basics for now and enjoy collecting in all the data you will need to progress
Ian.