If "wide range of markers" means wide range of barrel threads, you might want to go with iFit, because IMO they have the widest range of adapters and thread converters.
Each Freak kit has *one* barrel back, with one thread (e.g. A5/X7 or autococker) and multiple inserts and tips. that would be good for one type of barrel thread unless you can get a different-threaded barrel back by itself.
“This is the substance of the Way of the Samurai: if by setting one's heart right every morning and evening, one is able to live as though his body were already dead, he gains freedom in the Way. His whole life will be without blame, and he will succeed in his calling.”
- Yamamoto Tsunetomo