ok so here it goes. 100% het x 100% het = 25% albino, 50% Het, 25% normal.
in your situation....if you wanted an albino spider you would need a spider, and an albino aka homozygous
homo albino x homo spider = double het (not sure of percentages)
you need to raise the double hets and prove those together inorder to achieve the double mutation. one in sixteen chance.
If i am correct