It depends on the difficulty mode. SA and UFO are crazy hard for me on the high difficulties, even though UFO lets you get buttloads of resources it also has the highest overall amount of really hard patterns in the series by a good shot IMO, followed by SA. I never actually 1cc'd UFO/SA on Lunatic, although I did all the other games... until I stopped playing shmups nearly as much before 13/14 came out so I only did hard mode >_>; But I'm pretty sure I could do Lunatic just fine if I actually tried, for those two.
SA also has weird shot type tiering where it's like, ReimuA God Tier and then everyone else is fair compared to eachother. MarisaA is a -really- good one too but it's weird, so.
LLS is up there in the easiest Lunatics, by the way. Maybe followed by PCB, assuming you aren't doing IN with 7 base lives just because the game lets you. This again isn't counting touhou 13 or 14 :V Lack of experience with them.