Before you make a new aluminium tube for your 8 inch newt ,whatever you do don't take the weight saving too far. (Although I'm sure you would not make such a boo-boo!).
I say that because when I got my first "serious" astronomical scope (a brand new one produced by a supposed decent telescope maker) I soon realised the aluminium tube was really too flimsy.
Best of luck from Cliff
Photos, sketches and other images by SPA members