This is my V3. Its functionally the same as my V2 mod but the side buttons mount to the top shell now and its 69mm wide which is as narrow as I can get it. You will have to trim down the left and right click PCB (clip those little tabs off the sides. you'll know them when you see them) but otherwise its fairly straight forward. Some effort required and some additional screws required.
Weight is 57g with a AAA lithium
Additional hardware needed
4 M1.6 - 3mm for mounting left and right switches to mobo. Or glue them. Up to you
1 M1.6 - 5mm for the side button.