Hi guys, does the elite HK ability 'figures do not block line of sight for your attacks' work on large or massive models? I was thinking of using a Bantha as a moving wall, where my HK's can shoot at enemies the other side of the Bantha, while being safely out of line of sight from return fire. Would this work?

Yes.

'figures do not block line of sight for your attacks' works for all figures (it does not specify small figure or large figure).