[DMXF]

Priobe - You should be able to model the etubes to establish a good matrix as to exactly what each would accomplish. It would no doubt be quite involved and should ideally include correlations to various testing, as available (this aspect may be very important). You can calculate hole areas, passage areas, correct for some holes being at an angle, etc. You may end up with something that can be used to determine the tube number direction to go, or even maybe how to modify an existing tube by drilling more holes, etc.