hi
i cant help too much as only qualified in one type of extensions, but i can tell you what i know!
I have done Cinderella hair extensions, which is the pre bonded hair, which is the most popular and common type, eg victoria beckham, cheryl cole. It involves heating up the bond and attaching to individual hairs on your scalp about 1/2 inch away from the scalp.
We are advised the clients own hair needs to be at least 5 inches long as i remember.
Personally i use clip in extensions, you could try this but i think your hair will need to be longer.
www.cinderellahair.co.uk
hope this helps
x