Nope, that spring I ordered came in the other day...great idea, but no go for adapting to this hack.
Notice how many spring coils are in this type of AK hammer spring (which is the spring the OP used)...I count 3 per side.
Now count the coils on the single strand spring I tried...I count 6 per side, which is MUCH thicker than the first spring.
I tried assembling per the Youtube video...there is no way---no how that all those 6 coils fit in the forearm/bipod like the 3 coil spring fits. Doesn't even come close to fitting unless a lot of plastic is ground or cut away...which I don't want to do.
So, it's back to the drawing board. I'll order the old style multi wire spring like the original hack shows.