So when i was practicing using Samur1man's tutorial series and got to the two slide jumps, he advised to learn single input timing. But ive spent about an hour on these jumps and use a double tap for both and am almost always consistent.
Idk if anyone else does these jumps this way but basically for the first jump i tap jump right as the feet start to pokeout. Then do a full jump then go to the wall immediately after.
For the second jump i just wait until her head is about to poke though and do the same inputs.
Within 15 minutes of practice i went from around 10% success rate for both jumps to over 80%.
I'll try to upload a video showing what i mean, but i dont have a capture card atm so it might take a while lol.
But this seems a lot easier for newer players to execute than a single button jump.