after the quilt is finished, bound and washed the needle holes will close up & you will really not be able to see those little holes where the thread shows through- and it is doubtful she is going to sit with a magnifying glass checking out the quilting on the quilt- as long as your tension is good you are doing fine-- it is (easy) to see every little thing when you are right up close to the quilt you are working on- but when you stand back and look you don't see any of those things-
and invisible threads are good for wall hangings- gently used items but not for utility quilts that will be used/laundered often...and (can open a whole new can of worms) a *customer quilt* is not the place to experiment with new products- get some & try it out on something of your own first to see what it is like & the adjustments you need to make- some people love invisible thread- others have alot of problems with it.