You're a skinny minny (not a bad thing!) and from that split of cycling/running you are actually more focused to running I would say. Take that into equation with your weight also you are not going to push big FTP numbers doing both.... Unless you are a full time athlete!
I trained a lot with a guy who wanted so hard to be a triathlete, but worked full time as a solicitor so I eventually got the point one day when he was moaning about struggling to break 18mins for 5k when so fit and told him that he doesn't have the time or the physical capability to train for all 3. His best bet was to focus on the sport he enjoyed the most if he wanted to be competitive at any of them. He decided running was his thing, something I agree'd with, and he is running a hell of a quicker now over 5k and is competitive on local scene.... Sure he enjoyed doing all 3, but it was a proper jack of all trades situation which was enjoyable but he would never be competitive. The compromise was to focus mainly on cycling but still do swimming and cycling for fun/cross train/recovery.
Shamrock will know better than me but if you could push 3.5w/kg and run a 38min 10K in a duathlon that is likely bloody good standards is it not?
Whereas in a road race on the bike, 3.5w/kg will see you dropped swiftly and a 38min road 10k will not even see you top 50 at decent club level races. so all these things have to be taken with relevance to the people you are competing against and the specialisms they focus on versus the specific race you are targeting.
I got into running and later cycling as a way of loosing weight. I went from 85kg down to 47kg (to low) before settling around 55kg. I'm not a naturally athletic person so doubt I could ever reach a competitive standard in any sport. I think my main challenge is to find some new realistic goals to give my training focus. It had been all about the weight loss and my speed and endurance goals had been a away of achieving that.
I probably do favour running over cycling but half my cycling mileage is commuting and I'd much rather be cycling on a hot summers day than running so I'm unlikely to ditch one over the other.