Your best bet will be Al/Hg hands down. Netherlands should be full of readily available P2NP. You can use metal reactors however they will need to be epoxy coated or the acid will eat through the reactor after around 3-5 reactions (you do not want to be there when it happens). If you are looking for smaller large scale, you can simplify things with 200L glass reactors however you will only achieve around 7.5 or so kg of P2P per batch. We used 20L carboys with plastic hosing attached from the carboy to a glass adapter and added the HCl slowly in small increments. Once one carboy was added, we would attach another one. Then NaOH is added to basify everything and large amounts of water which will cool the reaction enough to switch to distillation. We used an extension column to deal with the splash back and steam distilled the P2P directly from the flask. This is one of the bottle necks, we tried peristaltic pumps, toluene extractions... in the end you will have to do the distillation for 8 hours. That is the best. If you are efficient and start the day early, you can finish in 12 hours.
We would place most reactants in the flask ready to go the night before. We would then wait for it to cool down after distillation, add some water once we are sure the flask wont crack, and suction all the crap out of the flask with a few rinses and some oxalic acid solution. You clean in place. You do not have to take down any setup. Imagine with 4 reactors going and 4 days in a row, you end with 120 kg of P2P. This reaction is terrible at small scale. Once you really scale it, you learn to love it and the yields increase. If you choose something like a metal reactor, its even better but your equipment may end up being disposable. It almost scales in a linear fashion, no real surprises.
Unfortunately, the Al/Hg is not so straight forward. Everything that is available about it online is almost all wrong. Many things apply to MDMA but not so much to Meth production. It can be scaled enormously with the proper understanding of how to create the catalyst and how it is introduced to the reactants. In smaller large scale, it can be done with the same 200L reactors in glass with 90%+ yields. In order to achieve those yield, the reaction must be violent. Foil will not work. It can also be done in 220L metal drums even with no mixing in 73-78% yields and the lid slightly ajar.
The shape of the reaction vessel, how it can hold pressure and how much solvent to Al to Hg makes all the difference. In a large metal reactor, it is also great but you will have to form the amalgam separately in another container and add it in to the Schiff base at the proper time. If you care about your reactor, you may also want to rinse the Al once it is activated with alcohol to remove a good part of the HgCl2. The best part: if done right no external heat is needed. Add toluene and siphon using a peristaltic pump.
Gassing is done by loading up your 200L reactors with conc sulfuric acid, and dripping HCl under slow mixing and passed through a CaCl column and into 220L plastic drums (with the option to open the lid) that sits on a drum dolly. Use multiple setups and drums. Use peristaltic pump again to siphon liquid/crystals into table top buchner. Rinse with acetone and repeat gassing.
Best method.