1) the PPH showed some pensioners doing it. How did they get on?
Pensioners have a life's worth of experience. My guess would be that they had relevant experience.
2) Gear (Steroid) dealers home brew extremely easily.
I can only talk for general manufacturing of illicit drugs. It's either done in a lab by competent (often professional) chemists. Or it's a simple product from often controlled base ingredients. Purity also varies quite a bit. Poor quality street drugs are common.
It's doable, but I'd be cautious. As amateurs we don't even know what can go wrong, and it's not obvious which aspects are important, when we do chemistry.
I never got around to cook anything.
It's mostly second hand information from addicts, especially from one friend hooked on amphetamine and into various RC, and online discussions.
My conclusion on setting up a lab was that it would be expensive, that the base products would be hard to get, and that I wasn't confident that I could make a safe product.
In short, there's a reason drugs are trafficked from other continents.