Tocsin, If I may make a suggestion , Hanzo Swords are all solid castings , use the resin cast as a template to create each piece in styrene that way you end up with a series of rectangular boxes, which you can epoxy together , the DustBuster kit from GM Props is the best set to use as it has the biggest speaker and if you fit it at the light point , the hollow box acts like a resonator and the sound is great , fit the electronics as you build once you have the main body , you can ‘dress’ the phaser with additional styrene sheets ! The measurements of which you can take from the resin cast prop . Then paint and finish . I have built several phaser rifles in this manner , for a number of people in the past , and should have created a set of card templates , to make replication easier as the last two had custom electronics and visible beam laser added and I wanted to make one for myself , but didn’t at the time.
I make it five pieces - rear body, handgrip, extension, forward hand grip and head , trace each piece first to get the sizes then re trace the ‘plant ons’ on each of the four sides that should give you all the elements you need to build a hollow version , if you do build this a set of measurements published here would help all those who desire to build one