Dunno if he's on rexnet (I don't frequent that forum) but Tony Knight (Knight Engines) in Adelaide has done some heads for me and they were superb. His porting work is bench proven and I believe his port shaping to be among the best around.

As above, it's an artform learned over many years and many failed experiments, letting your mates burrow out the ports with a dremmel will more than likely yield worse flow than stock.