The OP's question about whether to work on things as a prelude to getting into 14.1 vs. shooting 14.1 as a means to improve got me thinking about what I have been doing.
Capelle mentions that straight pool is largely a game of 90-99% shots, meaning that should be the probability of making each shot, if you're really doing it right.
I noticed that I was attempting shots that were too difficult to fall into that 90-99% window. That told me that my cue ball control needed work. Everyone has to make a nail biter periodically to keep a run going, but it was happening too often for me. That told me that my shot selection may also need work.
However, I was also missing a fair number (25% or so) of those gimmes. That told me that there was something wrong with my shotmaking.
I reviewed Tor Lowry's videos, video taped myself, and saw that there were flaws that I have been compensating for all these years. Like a golfer who adapts to his slice when on the course, I had been working around those flaws. You can do that in 9 ball, and 8 ball to an extent. Straight pool exposed the flaws in my game.
First thing I did was make sure my fundamentals were better. Got rid of my elbow drop, fixed my stance, and above all, started staying down on the shots with a solid follow through. This helped immediately. Some long shot drills Lowry talks about were just the ticket.
My advice would be to make sure your fundamentals are good, and then stick with 14.1 with an emphasis on hitting an index card size target for the CB between shots. I'm still working to hit my 5 meter target (20 ball run), but I'm close.
Sounds like very good advice. I have recently been working on tuning up my fundamentals after a two day session with Mark Wilson. My high run was 57 almost 8 years ago. Since then, I've had about 4 or 5 50s but nothing higher. My cue ball control has been very suspect, my fundamentals very flawed and my shot making very erratic. Hopefully, at my advanced age, I can still improve my fundamentals and maybe put together some reasonable runs.