Ok, but I think your goal is misguided - this is your first trip to Thailand and you want to meet lbs. You spend time in discos trying to pick one up - how long will you spend and how many lbs do you think you will see in a disco? Certainly you won't see 350+ lbs in one disco in one night.
If you have a lot of time in Bangkok, that would be another matter, lbs working in many of the make up shops in the big malls, like Siam Paragon, the Central chains, MBK, as well as a lot of the wedding studios around.
You can also try some of the on-line dating sites - but be aware many of the lbs advertising are pay for play as well. You probably will get a discounted rate being young and handsome, and have a bigger chance of a freebie, but don't count on it. Also don't make the mistake of promising something you cannot deliver - the lb news distribution passes news like lightning, so you can make life very difficult for yourself if you do.
Ladyboy Kisses, My Ladyboy Date, and Thai Friendly are websites that feature lbs. You will have to register, to view the profiles, and you will have to pay to get the contact details.