At 160w and 64kg I think 60g of malto per hour should be enough. I find the easiest thing to do is make one super concentrated (750ml) bottle with most of the fuel I need for the ride. So for 4 hours approximately 200g of malto and one scoop (~25g) of my favourite sport mix for flavour. Then I add salt (depending on weather) and some caffeine as well. It is best to prep this in advance and mix with hot water to get it to mix well enough. Leave it in the fridge overnight and your good to go.
You can dan plan and drink every 20-30 minutes such an amount that it your bottle is empty with maybe 10 minutes left. That is like 80-100ml every 20-30minutes.
Then I have a separate bottle with plain water that I refill if needed, usually easy enough to get water. And maybe have a bar or two to get in some solids (though I prefer to go without or with gels) and for emergencies.
That should get you through 4 hours without carrying lots of food or stopping for cafe breaks. I don’t usually like stopping, but if you like that, then adjust accordingly.
Don’t fuel with fats before or during a ride. As mentioned here already they just sit in your stomach and cause GI problems, same goes for high-fibre foods or proteins. If you want to limit carbs, you can limit after the recovery period after a ride.
If you want more tips on optimizing your on the bike fueling, the following threads helped me a lot: