I add another piece of tiger tape both above and below the first two, again matching up the marking lines.
I then remove the center two strips, which leaves me with a half inch of space between the two remaining pieces of tape insuring that I have a nice even height all the way across my seam. Since the tiger tape is 1/4 inch high, removing the center pieces leaves me with a space to make a seam 1/2 inch high. This is usually a useful height for my purposes.
If I want a shorter seam height, I will add another piece of tiger tape to each of the pieces left on the block, overlapping it so that I make a space for a shorter seam. As long as I keep the marks on my tape lined up I am able to easily make a seam which is even both in height and width. So, there you have it - the method to my madness!