Well done on finding your donor Kev
You may find that you need to collect an extra length of each size square tube !!
It has been a very long time since I made my chassis but I seem to remember that was the original quantity I had delivered & ended going up for an extra length of each
Not saying that the chassis can't be cut from that quantity but it will be very tight & don't forget, the jigs will use some of the 25 X 25 !!