cage and lesbentley, you are really helpful.  I learn a lot from both of you.

The process of making JCMs is working in my case, the problem is time consuming and it is not transferable.  With a new clothing mesh for Antonia, I have to do it all over again! The pictures below look similar to what I did months ago, right.  I have to repeat the same exercise again.  I'm looking for the technique that I can "reuse" what I've done.

V4 is using many magnets, I think it is mainly for the tons of morphs it supported.  I'm not sure how the V4's "magnetized" pose on the clothing suppose to work.  It seems to have no effect on what I've made.  The examples below show the bikini set I made for Antonia on Antonia (top) and V4 (bottom).  Of course, the V4 version is modified but from the same mesh I made for Antonia.  It is lower polygon counts than the V4's mesh.  The results are the cases without any JCM.  BTW, I haven't start making any JCM yet. I drew the red line to indicate my targeted shape.  I'm surprised that the bikini set I made for Antonia work on V4 even without poke-through!  But it is very ugly at the back.  In fact, V4's own texture mapped panties look very ugly at the back too, therefore, it is not too bad.  Of course, I'm not satisfied with the result on V4.