Perennial Egyptian Walking Onions

In favor of any vegetable that is perennial,  I'm curious to know how other people grow and harvest walking onions.   I have a two year old patch that is multiplying nicely.  The green shoots are mild the way I like but I and can't figure out how soon to take the "mother" bulb out.    And when I do, it's often just a hard, tight cluster of several small ones grown together so they're a nuisance to peel and dice a quantity for a large saute'.    I like the strong flavor of the mother bulb and they're just the right size for soups and canning, but I wish they would grow a little bigger than the 1 to 1-1/2" that I'm getting.

So I'm wondering if anyone has tried harvesting the seed tops just before they hit the ground and scatter the individual seeds a bit.   Or does that make the seed too vulnerable to drying out before taking hold with new roots?  

Hmmm, I searched for growing walking onions before writing my inquiry and when I posted it, it showed me similar threads that answered all my questions but did not show up in my query.    This happens often - I guess I need to find the instructions on how to use this website efficiently = haha!