So if I understand you correctly you are 100% FI when 4% of your stack is equal to your annual expenses. Your plan is that Bitcoin will continue to grow in purchasing power faster than 4% so although you have less bitcoin each year you will still maintain/grow your purchasing power. I’m about 50 now and figure I might have 40 years left so my FI calculation is based on my stack being worth number of years remaining * current take home salary. If you are researching a piece you might like to look at bitcoincompounding.com and wen-moon online bitcoin retirement calculators. I look forward to reading your research piece. 

 Yeah that's essentially the logic, although everyone is different. If you plan to have other income ongoing, the FI target can be lower.