2020 Rx 350 f sport performance OTD price.

Hi. I'm looking at a 2020 Lexus Rx 350 f sport performance with 20k miles on it. I've already went to see the car and just asked the salesman to give me a sheet breaking down the cost. It's currently listed for 41k and with taxes and fees it'll come out to $45,100. It's been sitting for 22 days now and planning on texting the salesman and letting him know what my out the door price would be to buy it. What would be a good initial offer? I'm thinking to ask 42k OTD knowing they'll probably wanna come up from that price with a hard stop at like 43,500.