While it is okay to sew with 1/8" seams, what I would do in this situation is -- after sewing -- reinforce those seams with MistyFuse. MistyFuse is a very lightweight fusible that will not add any stiffness or weight, but you have to be a little careful about handling it. If you Google, you can find some info about it. It is available on Amazon and eBay.
My concern would be eventual fraying of those narrow seams, especially if they are not quilted on both sides. That's why I would want to add a little reinforcement.
Edit: The MistyFuse would be applied to the wrong side. You could do it seam-by-seam, or a block at a time. Some people use MistyFuse on the entire quilt top (wrong side, of course) to stabilize it before layering. You could do that too, but it would take a lot more MistyFuse!