The problem with trying to identify King George VI stamps from the catalog descriptions with two or three stamps is the fact that there were a number of printings and they differ in some subtle ways from each other. The catalogs generally start with the description of the first issue and then if there is a significant change from the first issue they post that new description. But if you don't actually have a first printing you are not using an accurate starting point in your comparison. So you really have to accumulate a bunch of them to do it right.
It also helps to have a list of the printings and descriptions for each of them. This will give you a reference to use as you make your comparisons. The Bermuda Collectors Society published a detailed catalog that lists all of the printings and describes them. I used this as a starting point and then looked for stamps that seemed to match the descriptions. I then associated the Commonwealth, Gibbons and Scott catalog numbers with each printing. You can see the results in the scan below which shows the stamps as I identified them.
In the case of the Bermuda lower values, they were printed by Bradbury, Wilkinson so there are not big perforation changes like the ones you find with the Ceylon or KUT KGVI stamps. What you will find is a subtle change from a Line Perf that measures 11.9 that was used from 1938 until 1950 (Gibbons lists this as the a notation in the catalog); and a Comb Perf that measures 11.9 x 11.75 that was used from 1950 until 1952 (Gibbons lists this as a b notation in the catalog). You need a gauge like the Stanley Gibbons Instanta Gauge to measure the perforations accurately. The ones with the dots don't really work for close measurements like this. Don't be surprised if you don't have any of the Comb Perf issues. They are scarce.
After you separate the perforations, notice the paper and gum by looking at the back of the stamps. There were differences over time, typically the early issues were on thicker appearing paper with yellowish or off-white gum. During the war years thinner paper was used. After the war, the paper became thicker and the gum was whiter than early printings. See the scan below to see various Bradbury, Wilkinson printings over time. I look at the back of the stamps against black paper to see the differences. The Commonwealth and Gibbons Catalogs will list a date for the additional listings. Note the date and see if your stamp has the same attributes. It does help if you are using unused stamps so you can clearly see the paper and gum.
Once you separate the stamps by perforation and paper and gum, study the colors. There were some color changes but none are overwhelming. Notice the differences in the Browns compared to other stamps and then look at the Blue centers as you study your stamps. Try putting them on black paper and then on white paper under a strong light to make the comparisons.
I admit this is overkill for trying to decide between two catalog listings. But hopefully it will give you a framework on how to make your decisions.