I ordered some shogun inline hooks but 9/0 was the smallest I could find (wanted 7/0), got them anyway and sure enough theyre probably a bit big but i'm going to run the shogun on the rear and just put a shortened assist rig off a jig on the belly hook, is there any reason why I havent seen anyone else doing this?

I use assists on the big Magic Swimmers, mainly as I don't trust the connections between each part. But I've seen poppers rigged for GTs that way as well.

I would second this........with blooper poppers ok but not a zig zaggy stickbait.....7/0 inline shoguns with 9mm splits or jigstar inlines(not sure what size/Chris wong would know as he sells both your  starwalker lure(KY) and hooks).........the 9/0 will weigh it down a bit as well/which will be to the detriment of the lure.............with 7/0 and 9mm split.......the head pops back up pretty quick after the stroke.............believe me i spent ages dicking about with owner 3/0 trebs (all) or belly treb and single on the end......I found shogun inline 7/0 and 9mm splits the best with both your lure and the shimano ocea pencil..Dont go too heavy on the leader either...Hope this helps