Wil_2010
The biggest advantage that you have at this stage of your casting is that it is rather smooth.I note however that your upper hand is very low on the rod and would that make your sinker feel even heavier than necessary.If you go through the cast in slo-mo,you will see that there is not really substantial bend/load in the rod,even though the sinker looks to be about 6-7oz.
If I were you ,I would go and measure a few casts ,with your regular style,and then under the same conditions/wind etc,make a few, but widen your grip on the rod a bit more,maybe 6 inches for a start.Make a few casts and measure to see if there is an improvement.
Lastly,and this is me being overly critical,you may want to look up at an imaginery target in the sky a bit sooner in the cast.
There are room for vast improvements ,but discussing it now may confuse you altogether.Always try to make only one change per session,that way you will immediately know if it has an advantage.
p.s. Many big fish have been caught at 80-100meters,so dont let that dampen your confidence when presenting your baits,fish also tend to come very close inshore at night,and even more so on a pushing tide.Also bear in mind that a big bait slided out at 80m(casting sinker only),is arguably better than small bait and sinker, casted out at 60m, if you are targeting fish/sharks to match your tackle.
Cheers.