If you want, you can cut them all to your desired length to keep them consistant. It looks like the 6 iron will come 39.5"..so cutting .75" would be over length by many manufacturer standards.
You probably don't have the right tools to do everything properly, so I would recommend:
-(1) use a hack saw to cut your shaft lengths
-(2) buy some extremely rough sand paper to and rub the tip (about an 1.5") to secure a good bond between the epoxy and hosel.
-(3) clean the hosels...take a drill and drill out excess epoxy. Buy a wire brush and put that in the drill to completely clean the hosel out.
-(4) Add ferrule to the shaft
-(5) put epoxy on the tip and any excess in the hosel (I highly recommend you use a strong epoxy with glass beads mixed in)....use fishing line or a shim if the shaft doesn't fit the hosel tightly.
-(6) turn the ferrule(this will be very difficult without the right tools) My suggestion would be sand paper.
-(8) Use acetone and wipe ferrule to melt excess epoxy and complete shine