Nice work, lever idea looks great.
as for handle, I was taught to Hacksaw by an old English tradesmen, he Always used a hacksaw with a handle like this. Said that it worked better, as you use it the same as you use a file. Same technique.
Congrats! I'm adopted, and no matter what "they" tell you, it's who brought you up rather than who gave birth to you. My birth mum is Leslie, but the lady who raised me will Always be MUM. Good luck, kids are the Best job & the Worst job in the world :)