Here you go.
All the springs, 42278 at the front. Kit 418 incl. "bonus" to the rear.
And then each side by side - you can already tell they are grossly different. 42278 (with tubes for yellow and red) to the left.
And some numbers.
Yellow "hard" - 6 coils and 6.5 coils
Black "medium" - 6.5 and 7.25
Red "soft" - 7 and 7.75
All wire is 1.5mm and wound the same direction. For comparison, HPI silver (6543) are 6.5 coils of 1.5mm wire. So in theory same as the medium in the TRF set.
The 419 manual lists the springs as 42278 (red) so when I finally open my kit I'll compare those too.