LF TRADEMOD for Trim Transaction

Hello, I am in the market for a basic red trim for my guild's cape. I have found a potential seller who has offered to provide a trademod, but being a bit of a rookie when it comes to larger transactions like this, I'm feeling a little vulnerable.

Since the banning of Motoko, I have not heard of any other reliable TM source in GW. Could anyone direct me to one.

On top of that, if there's a thread that provides details into large trade etiquette for noobs like me to get some trading advice off of that would also be helpful.

Thanks