ALL YOU NEED is to actually just spend carats on support cards to max out SRs and get solid consistent boosts that'll perform for ages, you'd be blown away by how long mlb SRs will outperform SSRs for
the best way to go about rolling on support cards is to save up 200 so that the rolls get turned into an extra spark too for value
you might as well spark something that is going to be useful for ages, either grab a card you want to max out later, or grab a dupe on something that's good
YOU DO NOT NEED MAX DUPE NOW, you will get it from the universal dupe currency system over time
the only three cards that are going to stick around for a while are kitasan, super creek, and fine motion, the latter two most people likely have from rerolling accounts although fine motion was shilled far harder than super creek for some reason