Weighed packs are a huge problem, especially with these older sets. The best you can do is find someone with a good reputation / feedback score and cross your fingers. Read through their seller reviews (if available) and see if other collectors have commented on the legitimacy of the packs. If it's being sold through a dealer like Troll & Toad, while they don't weigh their packs themselves, people do sometimes sell them weighed packs (which they resell). I've had good luck and bad luck with businesses in this regard, so it's another "cross your fingers" thing.
General rule I take with old packs: if the listing feels dodgy, it probably is.
I don't have any seller recommendations myself, because I only buy Japanese cards of that era, but if JP cards also interest you, Brian at Pokevault is my go-to.