Featured Images and Marketpress questions

Featured image option:
How do i get the featured image to show a larger image rather than a thumbnail? every time i click “full size” it only shows a 150×150 thumbnail, and you have to click to enlarge, which takes you to a separate page with just that image on it.. . i’d like a large image on top of the product page without any thumbnails showing up , as is what happens when i insert it into the post. then I’d like this image to show up in a lightbox instead of going to another page.
also, how to i insert a separate gallery into separate pages? i’d like small individual galleries for product pages displaying color options and alternate views and whatnot, how can I achieve this?
here is my page for reference. the thumbnail at the top is what i’d like to show in full size.. under “Tab 2” is where I’ve clicked “insert into post” , that is where i would like to have some thumbnails in a little gallery.. i got the lightbox working, but thats about it. :
https://thegraphixlab.com/hook2/current/content/store/products/test-3/

i’m looking to go in the direction that another user went in, if this helps here is a link to his product page for reference: https://store.hillcrestpaintball.co.za/store/products/450/

in Marketpress, how do i edit the single product page template, for instance, if i want to remove the category from the product listing, or something like that, where would that be located?
is there any way to get the product options onto the main store page with an add to cart button instead of having to use the “choose option” button from there?
oh also, I’ve made a custom theme for the website and just use wordpress/marketpress as the back end, so there are no sidebars/widgets …?is there a way to list the shopping cart contents and a check out button at the bottom of each page rather than just a link? ? like an in-page widget or something?
ex: https://thegraphixlab.com/hook2/current/content/shop/