If you want to drop ladder work just mention that your insurance won't cover you for work on a ladder (which is true already in most cases). It gets the customer on your side, as nobody likes insurers. Since Slacky's accident we've dropped every single ladder job we do and lost only a tiny handful of customers.
Don't offer anything for referrals. There's research (that I can't find on my phone) that people are less likely to refer you if you pay (as the person they recommend you to will find out you paid for the referral so it will seem less honest). Just tell them you're looking for reliable customers just like them and do they know anyone they could recommend you to? Customers often seem to think all of us have rounds that are full to the brim so they don't recommend us.
Vin