changing simple product to variable

Hello – I have read about changing an already existing product to a variable product. My concern is that I have many simple paper book products with dimensions and weight that I will be adding the variable of “ebook” to. Will any of the preexisting dimensions or weight cause problems for the final outcome? I have successfully transformed about a dozen already, and they are showing up accurately in the shopping cart and the download versions are not adding any shipping – that was my first concern. (I made sure there were no dimensions in the ebook variation). I have not yet checked to see if the product actually will be sent to the customer via a link. I think what I am asking – is there anything I should be careful of that might cause future problems/challenges. I have many products that I’m going to edit. Thank you. I might add that I have had serious challenges with this when we had a different platform, and that is why I am asking now, before I do a lot of the work.