Small update. Finished my exams and finally had the hours to put in.
Ended up going with the full front end under tray/splitter so its best of both worlds.
7mm CD bunnings plywood w/ 3msq 200g weaved fibreglass with approx 500ml marine grade epoxy resin applied. All hardware is 316 SS and supporting mounts all bolt up to the chassis so it is very sturdy, will easily hold my weight (79KG). Total weight without the bumper is approx 7-8KG and total cost to build this was around 200 .... ish. Could have been a lot cheaper if i went with zinc/galvanized hardware.
Made a couple mistakes, first being the front being not long enough, which was my mistake. Measure twice, cut once!
Just need to complete the rear diffuser, will add more progress pics of that later.