Yeah, pubescens varieties like the shade and cooler temps.
Too much heat/sun and the flowers just drop off.
I have three pubescens varieties growing this year and they are all in full sunlight 19 hours per day. The Manzano Rojos and Montufars are both producing prolifically but my Pico Mucho only has 7 pods on it (though they are very large to be honest) despite being in a yuuuuuuge planter box. After setting those 7 pods, it basically dropped shitloads of flowers and refused to set pod number 8.
Then again we don't know real heat here in Finland - our summer daytime highs average 21c (70f). Our UV index is also around 5 during the peak of summer, which is quite low. I am also situated right at sea level. As a whole, though, pubescens grow wonderfully here but they do require massive sized pots to reach their full potential - 3 gallon pots are just not going to cut the mustard in this case. I had one of my Montufars in a 3 gallon pot and had to end up transplanting it to a 7 gallon pot at some point during July as it just grew so large that it became top heavy.
Totally inspired by your 3 gallon grow, Paul, I have all of my annuums sitting in pots that size and they are producing heavily. There are a few of them that look exactly like a stick with a few leaves and a ton of pods. Also growing 3 California Wonders in those and they produce more than we can eat.
Would I grow pubescens, chinense or baccatum varieties in 3 gal? No, definitely not when growing outside as I am not able to babysit them full time. If I had a greenhouse where wind was not a problem and things could be tied from the roof, then that is a completely different story. However, for annuums and frutescens I have found wonderful success in the 3 gallon pots (last year, I was growing some of these in 1 gallon pots and not doing nearly as well as this year).