UITable data type manipulation (string and format)


I have two questions regarding the uitable function or more in generel the double container type. I have the following table with the following values:

The table just uses an array of doubles called “data” with 10 columns. What i first of all want, is a proper formating of the numbers. I know there is the “ColumnFormat” option for the uitable, which is able to format the numbers according to the options, but no of the ones that I can choose make particular sense to me. For example in the black box depicted I choose “long g”. However, what I simply want, is a normal “numeric” format, that doesnt switch to E type expressions (which you can see in the orange box). I want to have the normal format BUT without the extension of adding 15 comma spaces to it (which the option “long” would do for example, which just is not what I want. Isnt’t there a possibility to format the numbers to numeric, without switching to E at any point and have 5 fixed comma spaces? (yeah I know there is “bank”, but 2 commas is too low for me, I need 5. does anyone has an idea on this?

The second question is maybe a little more complicated. In the red box, you can see some numbers that repeat at certain points. What I want is that for each cell in the column, where a specific number (e.g. 1.0078 which is the molar mass of hydrogen H) is stated, it is switched with a string (in my case H, which should stand for hydrogen atom). So that instead of the numbers, there is only a string “H”. I know that I can change the format of the column to “char” but I don’t know how to switch it up. And also to add, some numbers would require far longer strings! I read about a certain problem that when you want to swtich the number with a string, it matters how long the string is. E.G. for other numbers I need longer strings such as “HOOC-COOH”. Is this possible to do and if so, how?

Thanks very much in advance!