Brit, you can always re-use the vents on the glass tanks as well...why not?
If you are worried about lifting the new glass tank out of the old wooden one: first place some broad straps inside of the wooden one and make sure they overhang the sides of the wooden one. (Broad straps like in dog leashes). Then after finishing and letting the new tank set, you can lift the new one out of the old. LOL, just an idea again.
Don't discard the wooden tank, you van always use it as a "mold" for the next viv!
And why would the glass be lop-sided if the wooden tank is not?
I'm just thinking that at one stage or another the wooden tank would warp, rot or something as not only are water a concern for the long run, but heat is another concern.
Sela...will not say another word and leave it up to your dad and you to come up with a solution. LOL