You have to ADD a line for each entry in Prototypes/items.lua

icon_size = 32,

So the standard entry for each item will now look like

    -- New item; basic ressource for all silicon applications
    type = "item",
    name = "SiSi-silicon",
    icon = "__SimpleSilicon__/graphics/icons/silicon.png",
icon_size = 32,
    flags = {"goes-to-main-inventory"},
    subgroup = "raw-material",
    order = "e[SiSi-silicon]",
    stack_size = 100

I havn't played teh game with it but it didn't crash and the research screen displayed silicon so i think it's working.

Also you might want to edit the version in the info file in the main directory to .16. I did that just incase.

Awesome, got it working. But also kind of upset that I tried this previously, but adjusted something somewhere else which kept it form working. Whatever!