I'm not sure if you were asking about getting the center of this block together, but that would need some partial seaming. Line up one of the prints to a side of the white as you would if the print were the right length...but only sew a little bit of the seam, cut thread, press. Then you can add the other print to the print + white...it should be exactly the length of your piece now. Keep working around the white and you'll end up back at the danglin' piece that has the partial seam...complete it, and the center is done.
Geez, I hope this helps...I hope I read your question correctly...you've got great taste in blocks and fabs...the tricks can be learned...good luck on this one and those that will follow!
I'm so sorry, I should have welcomed you...noticed after all this that you really are new here....you're on your way...glad to have you!