Definitely need the estimate in writing and her to ok it--I find that awkward to do too when it's someone from my guild, but still force myself to do that as I've been burned--my first customer brought me a large crib quilt that had thickly painted animals in each block--and had told me via phone that she just wanted a meander. No way that quilt was suitable for meandering--the needle would have not gone through the paint or looked well. So I custom quilted and also did the "receiving blankets" she asked me to do too--gave me two pieces of fabric and asked that I just fold each over and quilt so she could bind for a receiving blanket! Then when she wanted a queen size quilt done and texted me about it, I quoted 1 1/2 cents/sq in if an edge to edge, 2 for custom and gave her the total for each and she said too expensive! This is well within the prices in my area and I decided then not to be chiseled down on price and have stuck to it since--does it mean I lose a customer or two--yes, cause there is at least one long arm quilter in my area that way under prices her work, but I figure I just refuse to stand for hours on end for less than $10/hour!
For a price list, check for the averages in your area, they seem to vary with the region you live in. And be sure to list those services like you did with having to add clamp on strips, etc. Don't underestimate your prices just because you are new at customer quilts, instead give a discount for first time customers, etc--always easier to give a discount than up prices later (unless the prices are increased area wide). good luck--I love to long arm and would like to make more $$ at it,but we have a number of long arm quilters in the area and each has their area that is a strength--or at least perceived strength-so I get those quilts that owners want done "modern". I also think that the availability of mid-arm and sit-down machines will mean more and more piecers doing their own quilting except for large quilts.