You don't have to make it harder to drive. It's a question of separating the cars from the bikes. Designate some streets for bikes and some for cars. That is better for both.
Where they cross, some junctions should prioritise cars and some bikes.
Also separate the pedestrians from the bikes on the same basis.
I tried those as well, but gave up immediately. I just use little squares of card, with two nicks cut in one end. Wind the thread / floss around and tuck the loose end in the nick to hold it. Works much better. I also find it's much quicker to unwind thread from - it doesn't have those blobs on the corners, so you can just pull the thread to the side and it unwinds.