Hoping somebody might be able to give some experience / guidence around a couple of products we are looking at buying

Im very much from the spinal tap school of electrics and tend to turn it up to 11 and whilst we have some great options in estim 2b and an erostec 312 box myself and a particularly sadistic lady are looking at some other options which sacrifice some of the nicities and pleasurable elements of the named boxes for a little more of a brutalist approach.

For context we use shock collars and cattle prods a lot and have used stun battons / guns on numerous occasions so are not naive to the risks and responsibilities that come with such type of play and as such we have in mind two options we are looking at and Im hoping somebody here might have experience of them

The first is the X1 screamlabs box

https://www.screamlabs.co.uk/ModelX1.html

This has a signigigantly higher output (in max mode) to an erostec and im told delivers the power in a much less smooth way making it doubly hard to cope with. - That massivley appeals for us as doe the asthetics and the sound it makes when being used.

Somebody recently reccomended an alternative to me though which is the Dom Orgel (the dom organ)

Which essentially seems a slightly more BDSM friendly version of a tucker telephone and that also really appeals to me - something about that hand held go anywhere manually driven box of pain...

I again like the asthetics mirroring the old field telephones and the price is signifigantly lower than the screamlabs

https://party-bizarr.de/die-dom-orgel-bdsm-reizstromgeraet/

https://eufory.de/LOB-TADEL-DOM-Orgel-V2-Reizstromgeraet-analog

does anybody have any experience or thoughts on either of these boxes - or indeed alternative suggestions (beyond the generally available estim boxes as we have experienced pretty much all these are and activley lookinf for something a little nastier)

I have been playing with shock collars and cattle prods as well.
Here my observation:
The market now is swept with very cheap products from China and I am a bit concerned with them. Often these do have a significant DC level in addition to AC. DC barely causes direct pain, but it can lead to burns (I have experienced it myself).
Also with cattle prods, I only use brand-name products such as Hot-Shot.
I have stayed away from stunning weapons, as I am more looking for a tool that can inflict significant pain, rather than the stunning-effect.

Also, I have developed and built several tools myself.
I found a voltage level of 500-1000 Volt to be ideal. Obviously with limiting the current to safe levels! Higher voltage is only needed if you want to penetrate clothing, Lower levels may provide inconsistent results depending on the dryness of the skin.
A very big variable however is the frequency. There is a very cool video here: https://www.youtube.com/watch?v=MMzU66IHe-k

The challenge when applying this research to commercially available products is that they don't produce clean sine waves. When adjusting the pulse length at a constant frequency, all one does is change the harmonics and the DC part. And often it is the higher harmonics that actually cause the significant pain.
And, unfortunately, in most cases the pulses are only positive (or negative however your interpretation). This again means there is a significant DC component. All this is information one doesn't find in the specs. It only becomes visible once putting the device on an oscilloscope.

This is why I design my own equipment. If I use any commercial product, I protect myself from DC or malfunction by running the current through a capacitor (something which I have also built into my own devices).

So I think the dom organ (field telephone) does indeed have a capacitor though I don't know if this will function in the way you describe

If the field telephone is rather old (pre-transistor), it may just have an AC generator that produces something close to a sine wave.
But there are quite different designs that were used...
Also, I am not so sure I would trust a decades-old capacitor. Breakdown of the insulation layer of capacitors is a common reason for electronic equipment to fail.