Antifouling advice please

[ss2016]

I have Hempel Hard Racing. It has worked well. I cruise at 24/25 Knots. My question is this. It's time to recoat. Is there any real advantage in two coats rather than just one? The reasons not to. It builds up over time/cost/work.

 

[Nigbb]

Update, the job is now done. Opinions on hard or eroding were 50/50 so I went with Seajet hard which is what was on it from last time, h guess only time will tell if that was the correct choice.

 

[Bandit]

You can put eroding over hard but not vice versa as the hard does not stick on well to eroding A/F.