In my opinion SEGA should extend the duration of the SG Scratch banners to the 6 months that JP does, but have following SG Scratches releases every 2 months to catch up and run them all concurrently. JP currently has a lot more scratches running at the same time, enough to require a scroll bar, so it should be possible. Though, eventually the number of SG Scratches may grow to require a second page or something. Furthermore, they should increase the potential "income" of SG by a factor relative to the lowered income when compared to JP, and the increased amount of SG items available for sale.
They can do so by first counting all the potential SG available to JP players in a month, do the same for NA, then calculate the percentage difference, and increase NA's SG income by that percentage. But that was only to account for the lowered income. Then to adjust for the increased amount of SG items for sale, they can utilize a similar process as before, add up the price of each Fresh Find item & set, as well as the SG Sale Sets, and all other things that cost SG. Then, do the same for the JP version of the game's Treasure Shop (which has much less stuff, and items return randomly), along with all the other things that cost SG in JP (which is just the things in the SG Shop, except they don't have those cosmetic sets AFAIK, SG Scratch, and Material Storage and other upgrade type things that we also have) and calculate the percentage difference between NA and JP within a month or two to have large sample size, then further increase NA's SG income by that percentage. Then, the method to earn that extra SG must be repeatable, and must be a similar level of effort and time as on JP.
Also, I dislike SG items being untradeable, though I can understand why they've done so. It's because if they allowed them to be tradeable some people would make hundreds of accounts, skip through the story for the SG and sell the items back to their main, or other people and sell that Meseta for real money, contributing to the bot problem. But at least make Fresh Finds and sets give 2 of the item when purchased.