there needs to be an option where set souls also changes your soul memory level. Reason being that Fromsoftware makes it a high priority to check soul memories first when scanning player's accounts. If your players level, stats, and items in inventory don't seem to match with your soul memory you will be banned. The fact that you've managed to "get away with this" doesn't count for shit because you are going to eventually get caught; injecting 300,000 souls into your account and using them to level up wont be factored into your soul memory, so a level 200 with around 500-600 soul memory for example (thats factoring in the hollows you kill at Things Betwixt) is going to raise an immediate red flag. Doesn't matter if you do this offline, and then go online, the numbers are still there, plain as day for anyone to see.
This trainer cannot be used online at all because of how the game works with soul memory. you WILL be caught. The only workaround is to use it offline and turn on all the invincibility cheat and run through the game, farming the enemies yourself to earn the souls you need so that there's absolutely no discrepancy. You'll leave a minimal trace, the only lead From will have is that you spent a pretty short time in the game and made rapid progress, but that can be easily fixed, since they can't track your progress offline.
Although there is the possibility of actually editing the item quantity for large warrior souls, for example, and then using those, since it will give you easy souls but also raise your soul memory. I don't know if they can detect that or not though.