Great research, Eva!! Henry Merrick, a clerk at the National Hotel, is correct. Some assassination books, perhaps the majority, do not include this conversation.
You know the task of which three books to take to a desert island (AKA Vienna)? I chose John Stanton's, David Donald's "Lincoln", and Ed Steers' "Encyclopedia" because I thought they cover the most questions and topics. (So, which three books would you decide on?)
Many years ago, assassination expert Mike Kauffman discovered a receipt showing that the government paid John Lloyd for his service as a witness in the conspiracy trial. How much was John Lloyd paid?
Bit of a storm my way and I may lose power so here's what I have. John Lloyd was paid to turn state's evidence to testify as a witness in the conspiracy trial.
The amount may be in "American Brutus" by Mike Kauffman. I think it was $50.