I used both squash ball and bungee cords
I have a squash ball under the pedal arm of the brakes and it worked fined, but you get used to the resistance pretty quickly and after a while it doesn't feel like it's enough.
I ordered the 6 pack bungee cables, 12, 18 and 24 inches, and so far I only used the 24 inch one.
I tried a single 24 inch cable just like in the above pic, but found it way too weak. So I hooked it on either side of the base and around the back of both pedals - ie a single bungee for both together and it feels great now 👍
When I did it like in the above pic, I found they get in the way of my feet. Wrapping them around the back of the pedals provides better clearance.
With this setup you can touch the pedal and get 10% throttle and brake quite easily and hold it, whereas before anytime you touched the pedal it would jump to 50% straight away. The squash ball gives you the real brake feel, but the extra resistance from the bungee gives you better feel on the initial push. Being able to push 10-20% on brakes, without ABS, will keep the car from snapping sideways in GT5 now, if you trail brake.
Very easy to brake without ABS now, and throttle modulation with powerful cars and less grippy tyres is sublime!
I'll try some of the shorter length bungee cables and see how they feel