Normally
solar controllers are rated for the greatest current and voltage that their internal circuitry will manage.
Thus you cannot use a 60A controller with 12v
batteries if the solar output is 20A @ 60v, because while the input is lower than 60A the output will be greater.
Therefore with controllers you need to look at the maximum output current at your battery voltage and the maximum input voltage of the
solar panels and make sure the controller is rated for more than these numbers. It is the maximum, input, or output that counts.
It also pays to download the manufactures handbook before you finally decide on the model. Sometimes the ratings are only nominal and have to be adjusted for temperature etc. (thus an 80A model can be 80A @20C, but only 70A with an air temperature @35C)
For these large solar arrays the best controllers are from Midnite and Outback.
The Midnite is newer and has some great features, such as a removable display and user
software updates.
The Outback is a little more conservative, but very well proven and reliable.
I think you can get slightly more leeway in current handling above 80A with the Midnite model and that would be helpful. It would therefore would be my choice although the Outback will protect itself if the current goes above 80A and in reality you are very unlikely to ever see this.
The Outback 60 is only suitable for a maximum solar array of 800w with 12v batteries, but the Outback 80 will go up to 1250w. (From their handbook). Outback have also released a totally waterproof model which would be great on a
boat but I don't know the details and it quite a bit more expensive.
I am less familiar with the current Midnite model range, but if they make a 96A model that would give you a little extra buffer. However check they meet these specifications at higher temperatures. If there is any suggestion that you might increase the solar array in the future go a bit bigger.
The other option is two 60A controllers. This gives you redundancy and slightly better
tracking, but the costs of 2x60A models are usually considerably more than one 80A model.