The main difference between LOCA and OCA is that LOCA glue is in liquid form. OCA is more of a solid that you can handle. However OCA requires an expensive machine that you will need to buy to take any bubbles out.
I would stick with LOCA, UV light is very cheap. If this is only for one glass only repair, I would suggest you just purchase a complete screen replacement assembly. LOCA, OCA and other technical repairs are meant for repair shops or people who do these repairs all the time.
Hope this helps!