I had a similar kind of trip that changed my outlook. Booked an ex-EU fare from DUB and as it was 100x easier to go from LCY and come back to LHR the same night, thats how I booked it. I also had a buffer of 3hrs, HBO, yada yada. Suffice to say it almost turned into a nightmare as the crew manning the LCY DUB flight ended up being delayed > 2.5hrs. When you're in a foreign city and relying on outstation staff to try and get your ticket reinstated, it tends to change one's perspective on these things.
Suffice to say I'm doing an ex EU from OSL to the southern hemisphere this year and I'll be organising my arrival at least a day (96% probably 2 days) in advance.
I wish you all the best with your journey and I hope that you don't encounter the same issues I had, but from my POV what you're doing I would never do again. Buffers of 1 day+ or a solid b2b is my game now.