Hi bonborn,
Good seedlings for first starting out, like most beginers want to buy, but it is relavent to your age. In a few years you'll know why !!
Firstly, please join a club. Sydney has lots of addvisers and experianced members to help you with your choices. Second, buy 1 piece of mature stock from a bonsai nursery rather than 6 seedlings.You will get far quicker results or even better, collect mature trees that are in the ground now and have been for 10 or so years. If you only collect 2 a year then in 5 years you will have 10 trees that you will be learning on all the time. Some stock I have collected started out 4 metres in height before 'resquing'. Collecting from the ground has methods that also need to be learnt for success.
Larger stronger trees will recover quicker than material as thin as just your finger.
There's a lot to learn even about putting them in the ground for 5 years and waiting for your plans. Put them onto a plate with the roots faned out under ground or something similar so the roots can spread and run sideways, the further they run and the more the top grows the better the nebari and the faster the trunk will expand. One of the lower branches will eventually end up being your new top down the track. Plant at an angle and let the tree just grow for the first 3 years or so. You should have by then lots of branches and more importantly more choices for your design options. A new top and branches can more easily be grown from a stronger mature tree. You should also by then be able to airlayer branches you plan to remove, that means more trees for you. It goes without saying that food and water on a regular basis will increase growth rate.
Good luck, and try not to be too impatiant. We were all there at your stage ourselves once upon a time.
