I'm glad you're home to keep an eye on him and test, lucky you.
You did the right thing, if you get a bg too low to shoot you can wait 30 minutes (don't feed) and test again to see if you get a shootable number and then shoot which you did or if you have to leave for work or whatever and won't be home you reduce the dose by 1/3 or 1/2.
A dose decrease is in order after that 43 yesterday and now with lower PS's. Small dose changes can give big results in both directions. He's been getting some steep drops all along it looks like, I'd like to see you even out his curve a little so it won't be so hard on his body.
Keep testing, knowing what his bg is gives you the power to correct it if he starts to go low.
Have you read the hypo info? Do you have a hypo kit ready? Become familiar with it because the more comfortable you are with knowing that you know what to do if it ever happens the calmer you will be through out, just knowing that you are prepared can ease your mind. Someone here suggested writing the carb % with a sharpie on the top of the cans because if you ever do have a hypo that is not the time to go print out Janet & Binky's list and start searching for carb %. After I slapped my forehead I did just that. I have the cans stacked in my hypo kit with the 8% on top because I want to try that first, 13% next, 16% on the bottom.
Shortly after I did that Harley droppped a little too low too early in his cycle for comfort, I got the 8% carb can and let him lick the gravy and that did the trick and brought him up gradually. I was very thankful for that tip.
You're doing great.