Holdsworth doesn't do much tapping at all. Probably none in many, many years.
It's all done with one hand...the connection is the legato feel.
Thanks for the correction - not sure why I associated Holdsworth with tapping. Maybe I've just heard an unrepresentative sample. But he does try to minimize the effect of his picking, doesn't he? I think of him as having a very, very light touch with his right hand.