I go back and forth on this and switch it up. Currently I am using a little of both. Not a solid wall, but a few solid lines here and there to guide some Imp troops certain ways.
A really good spread is tough to manage, but with jetpack loadouts they can be rolled. I haven't used heavies in a long long long time, but if I were to use them again, spread walls can really get annoying.
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Level X Rebel : 100k+ Medals : Joined the Rebellion 12/28/2015