Trying to Keep Opponent in the Pot with top set

Hiyo,

I'm primarily a live player currently trying to play as a profession. I live in Germany and play in my local Casino; they play 2/4 with ~2.5% rake and 100€+ buyin (no max). The field primarily consists of very bad players (including bad regs) plus a few pros.

€2/4 NL (9 handed)
LJ Hero (€600)
CO V1 (€500)
BB V2 (€200)

In this hand, I RFI with J♠J♣. There are no good players left to act, so I decide to go 16€ rather than my usual 12€; there's almost no chance I'll get punished for doing this. CO and BB call, the rest folds.

CO is a player I've seen for the first time today. He was playing a heads-up tournament on GGPoker on his phone while sitting on the table. I assume this actually makes him bad; I don't think any actually good player would do this(?). He has seemed on the tighter side; nothing crazy, no 3betting all day. BB is a bad reg but his style isn't really relevant.

Flop comes J♦3♠4♠ (Pot=50€😉, giving me the super nuts. BB checks, I check, CO bets 28€, BB folds. I min-raise to 56€ and CO folds.

So my thinking was something like,

• 1. I could call but there is a flush draw here, and also everyone in the casino just loves trapping with sets even when it's not good play, so it's kinda expected and I'd prefer to do sth else
  
• 2. A minraise sometimes looks strong, but actually (1) this doesn't look like a small raise, and more importantly (2) I think most bad players just play their cards, and if CO has a flush draw or pair with backdoor equity or anything, I just want to give him the price to call.
  

But it didn't work, and this is the kind of hand that really bothers me. Like it's easy to get upset about making bad calls or folds or whatever, but actually if I could have kept CO in the pot for one more street and didn't, that's a big deal!

So against the player described here, what do you think is the most effective play? Should you raise larger? If so, how large? Do you think it looks weaker if I just throw 60€ in there rather than counting to exactly double? Or should you take the risk of getting beaten by the flush and call? (And if so, how much time should you take before calling?) Or should you have lead here? I often feel like I don't know the most exploitative play when I get the nuts, and it's hard to improve because I have no database for my live play, and I don't think GTO matters here at all. You can throw all ideas about balancing or playing my entire range out the window here; neither of these two opponents is good enough or paying enough attention here for me to worry about that. I just want to get the max out of this specific hand.

Idk, overall I just feel like there had to have been a way to get more money here. Obviously I'm blocking all the top pairs here, and the fact that the CO bet at all is already a nice surprise, but now that he did he probably has something, so the fold really stings.