GJ you're grappling there with the practice of trading versus the theory.
1) Trading Plan. You need a strategy in the market. For some types of tradinng its a good idea to write out a plan, others no need. Someone like Pisces doing medium term investing would probably laugh at writing out a trading plan before every trade, but he nevertheless has a definite defined strategy in the market. For me, I don't write a plan down for my medium term long only spec investments, but do make notes and analysis in researching a stock in various ways. For my short term TA-based Options trading, I do write a trading plan for every trade, or try to. I'm sometimes lazy or time poor and just enter but really shouldn't. Earlier this year I did an update of my Trading Plan template. It works like a TA checklist mostly but also has some FA notes, an options calculator and a summary of reasons for a trade. I expect its more comprehensive than almost everyone.
I remember reading once that some guy invented a checklist for use in hospitals that greatly reduced surgery error rates. So just like a top surgeon could easily turn up and see the problem straight away, going through a checklist improves outcomes. A Trading Plan has the same purpose for me. It is also excellent mental training for someone developing their technical trading skills.
2) The reality is that the R/R of your position is constantly changing. Trying to constantly adjust for risk though will cause you to be stopped out.
One response to the issue is to consider 3:1 R/R a hurdle for trade entry, but after that ignore it and just manage the trade as appropriate for its circumstance and logic.
Another approach is to recognise the diminishing R/R in your exit strategy. So on my options trading (when trading well!), I set entry positions at 3:1 to target but average wins are 2:1 by my records, so in effect taking the profit early due to diminishing R/R of continued holding. It works as average losses are 0.5.
I've also found that stops generally have a negative edge and completely redesigned my trading after analysing some 200 trades to avoid them. The issue I was finding was that in your example the stock would say move to 1.10, then retrace back to 90 and stop out and then continue on to my 1.30 target, or whatever. So I was stopping and losing more than taking profits. Had to design out stops by shifting to ETO trading.
Bottom line, you cant be too rigid and trade by textbook, you need to design an approach that adjusts for the sort of issues you're identifying from your experience in the market.
(20min delay)