I have no doubt in my mind that there is not one amongst you who would have travelled round that bend at 20 mph. So lets cut to the chase and debate the issue rather than making it about me.
I do.
I was taught to do that.
I still do that. Though I don't claim a particular speed would be safe, just any speed that is slow enough to be safe.
OK, not a personal attack on you, you learned something today about your driving and the road you were on. That is a good and positive thing, sadly not every driver would have stopped to think about it as you did. Most would have blamed the cyclist, the sun, the road designer, in fact nearly anyone and anything else other then question if they could have done any different. So you are doing well so far.
Anyway, The solution is, as has been said, to only drive as far as you can see to be your safe stopping distance. If you can only see 10m around a blind corner then your speed should allow you to come to a stop within 10m given the road conditions, even if that is less then walking speed.
I will happily blast around country lanes at the speed limit but I will also slow to a crawl if the next bend or junction is blind. This is not because I am a cyclist but because I learned, when I learned to drive, that sometimes there is something around the corner that could either kill me or be killed by me if I wasn't able to stop in time.
OK, my anecdote.
I was driving on a winding lane in mid Wales, a few years ago, and approaching a bend to the right. It was a blind bend that had many chevrons on it and high hedges on both sides. I think I was down to about 10-15mph and aiming for walking speed until I could see further.
As I got to the start of the bend an articulated lorry came into view coming towards me. The lorry was on the other side of the road and well clear of me but the overhanging front end of the oversize load it was carrying, as it rounded the bend, swept over the roof of my car causing me to instinctively duck. I came to a dead stop very quickly as I was no longer able to look above the dash. Had I been driving a taller vehicle, a 4x4 or a van, the load would have hit my vehicle.
If I had been driving faster then I wouldn't have been able to duck and stop safely.
Annoyingly the escort vehicle carrying the sign that said 'Caution, oversize load following' was following behind the lorry it should have been in front of.
Anyway, good for thinking about the incident and wanting to figure out how to make your driving safer in future.