Zenes are generally bad. Strong analgesic potency, but poor receptors affinity. For people loving strong sedation and long half-life, who got high tolerance, they are good tough.
Additionally, if you use them daily for several months, they will destroy your tolerance for months if not years. You picked the worst ones to try tough. Meto got very bad WD and is not suitable for smoking if not prepared properly. Buto is just junk. Etazene is the best of the worst, 90x potency, and it's the only one with a smooth taste. You can't smoke it pure, unless u have a strong tolerance with f3ntas. And there are lot of sellers claiming to sell etazene but they sell mix of etos. If you get legit eto, it's short acting, but it's nice to smoke (put 2-3 mg in glass pipe, add 20mg caffeine, head up, take the hit when pipe ball is full of smoke). It give a nice high, but don't expect to be like the golden age f3nt. And in 3 days the magic will be gone. So it's suitable only to use it like once a week for a nice nod, for the rest stay on maintenance with o-dsmt or dipyanone and wait for the next good class of strong rc opioids. Stop playing russian roulette buying fentadope on the street. Hard/rare to find is Protonitazene, this is 180x and it's long acting, euphoric (but not as much as etazene) and lot less sides/wd than Meto. But still, tolerance killer. Not suitable for smoking. Best used snorted, so do volumetric dosage , start LOW (300ug/spray press).
I still don't reccomend to switch to zenes, and take this occasion to taper down with o-dsmt or dipyanone and enjoy when you reach a low tolerance the new RC opioids that will come out, chinese finally started focusing on the proper classes, with low potency but great receptors affinity.
Give up with fentas, unless you can arrange with a chemist a batch for you, you will never find it on DNMs or on the street in pure quality. Plus fent4 HCL is hell boring compared to golden age f3nta analogues.
A great new fent analogue was going to be released in EU, sadly seller vanished atm so nothing in sight.
Choose wisely and stay safe. NO PM regarding sourcing pls.