A Body glove box - newly made

I do need 2 of theses myself for my 66's and have got the glovebox almost down pat and able to make them with no webbing. but getting that sharp crease on the outer edge in there isn't as easy as I though it would be and need a good "push block" for my machine, the Cutting out jig is my main problem. I suck at cutting a straight line by hand.