I am looking at a new build as follows:

CPU  i7-8700K

MB  Z370 Extreme 4

I am very confused about the memory.  I want to stay with G.Skill memory since I have had good luck with it in the past.  I do not have the experience or expertise to fix memory problems so I want to be sure I don't get incompatible memory.  The memory I picked out was G.Skill   F4-3200C16D-16GTZB which is on G.Skill's QVL list as tested for this board but not on ASRock's QVL list.  However F4-3200C16D-16GTZ (without a B on the end) is on ASRock's QVL list.  I would like to use the F4-3200C16D-16GTZB because it is cheaper but I want avoid any problems with it not working on first boot.  I am not sure what difference the B at the end makes.  Is this a reasonable risk to take or should I stick with memory from ASRock's list?  There list is limited and I suspect it is out of date.

If I use memory on G.Skill's list, will they help me resolve the problem and and accept returns for different memory if I am out of the RMA period from the seller?

I am open to recommendations or suggestions.  Memory is very confusing to me.  Thanks to anyone who can help me.