ahhhhh ok, This is what we learned from trial and error please consider this very carefully...
...We had an IR position in our league. With an IR spot come questions such as who qualifies?, how long?, what kind of injury report qualifies as IR, and so on. Believe me not every question will be covered and owners WILL try to bend the rules and stack the roster. Your job as a commish just doubled because you have to police everyones roster every week.
What we ended up doing and it works perfect is having a extra BENCH flex spot (any position) that owners can use on anything or anyone. They can handcuff there #1 pick backup for insurance, use it as a future IR, or just stack on Kickers (sarcasm). This spot can be used like any other spot on the roster meaning that you can do add drops as you wish.
Whatever way you choose, I recommend to limit it to one spot.
Any questions please let me know.
Best Damn Fantasy Football League