Ficus - fusing trunks
 

I have a Ficus Rianne (cultivar of Ficus benjaminia) on which I would
like to fuse trunks as mentioned here
http://www.bonsaihunk.us/ficusforum/...echnique2.html

Can somebody answer the following questions please.

1. If I am fusing two trunks what will happen if I lightly "shave"
the inside of the both trunks. Will they merge together to form one
trunk? Is it possible that one trunk might "reject" the other causing
the plant to die?

2. Can this be done with mature bonsai with 1" trunk? Is there a
limit on how many trunks should be "fused"?

3. Anything else I should know before I do this?

Thanks.