There seem to be strong opinions about whether having BIN is OK on multiple marketplaces. If one has Afternic Fast Transfer activated, there is a question of exclusivity there for the BIN. Sedo customer service had alluded to this possibility, while not confirming this.
Granted, it's probably unlikely that the same domain would sell on two marketplaces on the same day. But if this did happen, what are the consequences?
To me, make offer makes more sense on Sedo, if you using Afternic Fast Transfer for those domains as well. An alternative might be to forgo the FT, and simply have BIN for regular listings in both locations.
This actually happens - Double BIN sale. I know from my own experience. Happened, and not just once.
Question is, how you manage it. Also if you take the risk. Like they say, no risk no reward. Everybody has to decide.
Having BIN in one place and make offer everywhere else is the safest thing though, and a sensible thing to do.
But if you have high value domains, what I would choose is to set a min offer / floor at Afternic and use NS3/NS4 and BIN at Sedo. In this way you have the best of both worlds - without risking anything.
Thing is, the more you sell for cheap the more the risk of double sale.
The higher the prices are, the less the risk.
There aren't 2 buyers at the same time dropping $10k on your name, be sure of that. I had double sales because I was selling low xxx range. Not anymore.
My first 4-fig sale was a domain I didn't value much (not a .com) . I had it listed for $100 on one platform and by mistake I had it listed for $1500 on another platform. At the time I didn't know however that that was a single word, actually.
Edit: I won't mention which the platforms were, at the time I was on several not just Afternic and Sedo as I was testing everything out there, and it wasn't this pair exactly.
The domain sold for $100 and $1500 in 2 different marketplaces, minutes from each other. I solved the issue as I knew best. Pocketed the $1500 - fees. Escaped with a warning. Note, it might not be your case, you have been warned.
I did not have a double sale in the last few years - at all. (Edit: even if I had BIN in 2 places, or 3 places sometimes). Keeping my prices high, retail. Since then, again no such double BIN sales. But I have been also careful and watching everything ( I check my phone if I wake up overnight, if anything sells I delist it elsewhere ).
TL DR: I'd recommend BIN at Sedo and make offer at Afternic with the lead lander, NS3/NS4. This is a safe setup, and works well for higher value names where there's negotiation in most cases. Once you sold something, delist it from the other. There's no chance of double BIN clashing in this format as there is only one BIN.
Later edit - Important. Forgot to mention, the double sales were always like $100 + a higher price elsewhere, but in all cases, the $100 buyer was a frontrunner who knew something and was trying to get the domain for cheap, to sell to the final buyer. This is way more common than you think. I've seen several of these over the years. (BTW - Anyone has encountered the poor student that needs a domain yet? Or a gift to his sick and disabled sister....? )