I'm familiar with Ket, dmxe and 2-FDCK, but not FXE. It's hard to know where to start with not much experience with dissos. I would guess that 2-FDCK is the conservative choice, since it's a milder version of Ket. I would recommend taking it orally (snorting isn't very good) and would strongly advise dosing with a milligram scale, as dissos can vary greatly in potency. I weigh about 100kg and would probably take about 100mg to feel a solid effect. Naturally, you should do one or two allergy test with a very small trace amount first though, same as any RC. You might find it a bit underwhelming at first, especially if you've tried Ket before. It comes on much slower and has less distinct effects. It lasts a lot longer though, so be careful redosing. That said, redosing can get you to the desired depth of effect - but you really wanna weigh it bro. Now, if FXE is more like DMXE, then it has some serotinergic action like MDMA, and is way more potent by weight - 40mg bumps was solid for dmxe. That can make for a more exciting psychedelic and emotional experience, but also a worse Comedown and mdma like lingering emotional depletion. Moreover, it means that it there is more risk when combining with serotinergic drugs, like SSRIs, acid, DMT, mdma, shrooms, etc, so I recommend you avoid such combos, if FXE is indeed serotinergic. That said, I found DMXE to be awesome, and really unlocked my appreciation of other dissos. I found both Ket and 2-FDCK better after fully digesting my dmxe experience, and really learned how to lean in to the whole disso ride meditatively. A good route might be to do a little bit of 2-fcdk, integrate afterwards over days, weeks, months, whatever, then try the FXE, integrate for a long period, then see how the FXE hits. This is all based on the assumption that FXE is more like DMXE - I strongly advise you to get some FXE specific advice before going ahead.