There is nothing particularly tricky about making Parodinal or Caffenol, or most other home brews. The only two things that could be an issue are the quality of your raw materials and the consistency of your measurements. Once you have that sorted, the rest is the proverbial walk in the park.
With the coffee in Caffenol, it is possible that from one brand to the next there will be variations in the caffeine content. The only way to avoid this is to use pure caffeine from a chemicals supplier, but that may be impractical for a number of reasons. That said, hundreds of thousands of people all over the world make Caffenol, with all the coffee brands that exist, and they get their films developed with remarkable consistency. So my advice is to give it a try and when you do, stick with the brand(s) for which you can find references on the net. We do not have Folgers in South Africa, but our local brands work well enough. Chances are, the worst the coffee tastes, the better it will develop film .
As for Parodinal, I have developed countless films with it. I still have Rodinal from 25 years ago that I have kept all through my digital-only years, and it still works, so I could use that as a reference. The wonderful thing about "original" Rodinal is that it contains only one developing agent, para-aminophenol (4-aminophenol). This molecule is the basis of many commercial chemicals, including paracetamol and metol (used in D76). There is another recipe to make a Rodinal developer using metol as starting material, but my assessment is that it is a very expensive way involving more noxious chemicals to get to the same end result as Parodinal. I have also made Rodinal according to the formula given in the Film Developing Cookbook. That formula uses potassium bisulfite, sodium hydroxide and 4-aminophenol hydrochloride. I could only source pure 4-aminophenol, and dissolved that in a titered amount of hydrochloric acid before following the rest of the recipe. My FDC brew works (although it is very dark in colour), as does parodinal, as does original Agfa Rodinal, and I see no difference in the results from any of those. Of the three, Parodinal is the easiest to make, and is certainly cheap enough for the purpose of film developing. If you weren't on the other side of the globe, I would have made you a three year supply and sent it with my compliments ;-).
Rodinal is an accutance developer, and very easy to use, as are all the single shot developers. I use it always at 1:50, although others also use it at higher dilutions for stand development. As I use it, it is not a speed enhancing developer and one has to get exposure more or less correct. The maxim "over-expose and under-develop" in that case is somewhat true, perhaps. It gives a very nice negative for printing, with the overall tonality just right, to my eye at least. If I expose and develop a Rodinal negative correctly, I can print straight onto grade 2 with almost no need for fancy tricks unless it was a very difficult subject to start with. Rodinal produces more visible grain than D76, Xtol etc. Although it has never bothered me in darkroom prints, it is a slight handicap for scanning, especially if you apply sharpening to the digital files. I am not much of an expert when it comes to digital processing, so there may be an easy remedy for this but I haven't found it yet.
If you are only ever going to scan your films, then probably Caffenol is going to be preferred. You could of course also use Xtol - it is similar to Caffenol in properties. I could only source Xtol in 5 liter packaging, and I doubt that I can get through 5 liters of stock in the six months or so it will last. At least, I can't predict my film consumption that accurately, so I tend to prefer the single-shot type developers. Another thing about Xtol is that it may disappear along with Kodak - one doesn't know. The formula is not easily prepared as the chemicals are difficult to get hold of. Caffenol is an excellent alternative and will be available as long as coffee is. Its only weak point is longevity - one has to use it fairly soon after preparation. I have stored it in the fridge for two weeks with all the air squeezed out of the bottle, and there were no problems. But I suspect that six months would be stretching it.