Customise Gravity Forms for Wordpress

I am building an online store which sells products by weight and by qty. I am using Gravity forms on Wordpress. I have modified the default product field to allow decimal figures and renamed the labels to allow for purchasing items by weight. My solution above is not suitable because validation and labels are incorrect for items which I wish to purchase by quantity. As such, I need to build a custom product field and integrate it within the gravity forms plugin. This field will have ALL of the same properties as the standard product field, however this particular field should be called ProductW (which is the product which I can purchase by weight, and will allow for integer values. I will attach a few code snippets and an image to show how this should display within gravity forms. The successful bidder will already understand how gravity forms works, have a gravity forms developer licence and have experience of customising the gravity forms plugin. The successful bidder will be available via SKYPE and have a fluent level of English. This is no more than a few lines of code / a few hours work for somebody with the required experience. Image attached - you can see a new product field called "Product Weight" txt file - Some custom code which I have in my own plugin. As this is such a small project, no deposit will be paid. Payment will be made in full after a successful demonstration via screenshare software. e.g. [login to view URL]