One thing you just have to accept as a clyde, nothing is going to last as long as it would a 60kg climber. Its also going to flex more. Doesn't mean you can't ride lite gear, just expect to have durability issues.
24/20 spokes is pretty mid range, but if it is only a lowish profile rim you are going to be working those spokes a lot, and I'm betting they aren't super top quality spokes either. You may have just had one weak spoke......but I'm betting you'll have more go in the not too distant future.
Don't have people tell you than because you are over *** kg then you must have a certain number of spokes, but yes for similar usage us clydes need a few more. It is a combination of your weight, riding style, terrain, road surfaces, maintainance, and tolerance for replacing parts or breakage.
For your racing wheels for instance, 20/24 with a good rim might be perfectly ok, but since they won't last for ever you may not want them for your 30,000km a year training on country roads (you do train 30,00km a year right??
).
That is where the beauty of custom built wheels come in. You don't have to take a set of wheels designed to suit a wide range of people and thier needs (so they can sell a lot of wheels) you will pick all of the parts (and colours) to suit you and your needs. AND servicing will be cheaper/easier.
There are thousands on threads on every forum about which rims and hubs and spokes and patterns are good, read them, then talk to a wheel builder, and enjoy the process!