Hacker News story: Ask HN: What tool for negotiating/discussing scope items for fixed quote?

Ask HN: What tool for negotiating/discussing scope items for fixed quote?
I'm a solo freelance web developer. One pain point I haven't really been able to solve looks like this: Client wants a fixed quote for some features. Typically this is a "phase 2" after we have already done a fixed quote with delivery, and trust has been built. They sent an email with a paragraph on each feature/change they want. I send some follow up questions. They send some answers and add a couple more features. Their tech person chimes in with a few more comments. I send a quote itemising the features. They ask how much if we change one of the features in a certain way. They say not to worry about the first feature we talked about. They start adding screenshots to the email threads to describe specific features. This is perhaps the only part of the business that I find tiresome in terms of admin. It's quite hard work getting all the email threads together, keeping track of the comments, making sure I have enough details to quote, etc. What's a better way? Obviously the idea of Github Issues occurs, but it would be a tough sell getting a client to write a separate issue for every possible scope item, and having "business" discussions in the Github Issues feels icky somehow. (I don't think my client contacts nor I would particularly like my fees to be visible to other developers who might be involved.) I have tried using a spreadsheet, where each row is a feature, and each column is a round of discussion on the feature. Which sort of works, but lacks formatting, and it's hard to incorporate screencaps. These quotes are generally in the $5-15k range. Usually it's a codebase I built from scratch but will be handing over to their team to manage/maintain. Would love to hear any tools/techniques that have worked for you. 2 comments on Hacker News.
I'm a solo freelance web developer. One pain point I haven't really been able to solve looks like this: Client wants a fixed quote for some features. Typically this is a "phase 2" after we have already done a fixed quote with delivery, and trust has been built. They sent an email with a paragraph on each feature/change they want. I send some follow up questions. They send some answers and add a couple more features. Their tech person chimes in with a few more comments. I send a quote itemising the features. They ask how much if we change one of the features in a certain way. They say not to worry about the first feature we talked about. They start adding screenshots to the email threads to describe specific features. This is perhaps the only part of the business that I find tiresome in terms of admin. It's quite hard work getting all the email threads together, keeping track of the comments, making sure I have enough details to quote, etc. What's a better way? Obviously the idea of Github Issues occurs, but it would be a tough sell getting a client to write a separate issue for every possible scope item, and having "business" discussions in the Github Issues feels icky somehow. (I don't think my client contacts nor I would particularly like my fees to be visible to other developers who might be involved.) I have tried using a spreadsheet, where each row is a feature, and each column is a round of discussion on the feature. Which sort of works, but lacks formatting, and it's hard to incorporate screencaps. These quotes are generally in the $5-15k range. Usually it's a codebase I built from scratch but will be handing over to their team to manage/maintain. Would love to hear any tools/techniques that have worked for you.