Do you think you could provide an illustration of your custom form? Please send it to firstname.lastname@example.org
In the meantime, let me try to to give you general information:
To adjust the size of a field as a whole, please select the field and hover around it, as you move toward your right, at the right margin (the right border in dash line of the box that encloses the entire field) you will see the resize handle (this is the two-vertical-lines with the right/left arrow on each size), click it and drag it to adjust the size.
To adjust the size of the field input box (that is, where the form filler input text), please select the field, and click on the resize handle that you see on the right size of the input box..
To adjust the size of the box that contains the field Label, select the field, again, you will see the resize handle on the right size of this box. You will only see it if your label positon is "Left Aligned" or "Right Aligned".
To adjust the alignment of your labels, select the field and on your right you will see the Fields Property Panel, click on the "Label Posistion" drop down and you will see the options that you can select.
To change the font of your field label, please select the text of the label and select any of the formatting options available on the toolbar (font family, font size, color, text alignment ...etc)
To add field above or below or side by side, select the field and click on the (insert) + icon that you see either on the upper left corner or the upper right corner. You can also click+drag+drop a field to a different location.
Did you get anywhere with this Debi, I have the same problem and its mind numbing. Having to have one label change the size of all labels on the form is insanely bad application design.