Ok, what BRAND is the UVB, there are many out there that do more damage than good. Also if you are using a MBV bulb a second UVB could actually be throwing out too much UVB. Too much can be just as problamatic as not enough!
Basking ontop of each other is a sign of dominance, blocking all the good UVB rays from the weaker one. There are many stories on here where babies have lost libms while fighting with siblings, or even worse died due to fighting. Some people have housed them together for years but come home one day to a dead dragon or two. I dont mean to scare you, but for the sake of your dragons its important they be separated. Also if they are male and female, the male will be sexually mature much sooner than the female and pester her all the time, stressing her out, trying to mate too soon. This can be a very hard process on a female anyway and you wouldnt want her to suffer it too young.
Im not sure about the size of your tank, is it possible to put a divider in to slpit the cage in two??
The stick on thermometres can be up to 20 degrees off, so i would change it for a more accurita digital one with a probe. Just be sure to leave it on the basking spot, directly on the spot, for 45 min before taking a reading. If you had a little more money you can get a temperature gun, you just point and click for a reading, they are very good.
What type of calcium are you using, is it with or without D3? twice a day is a little much, 5 times a week (so 5 feedings) when they are babies, and 2 times a week with vitamins, then 3 times a week when they are adult.
ALso what type of greens do you offer, again as there are many that are bad. Have you seen the beautiful dragons nutrition chart? its very helpful and colour coded.
Buggsy