As a general rule, ask yourself what you would do if you were not going to be reimbursed. Because you might not be. Thus, spend as though it is out of your pocket until it is not.
Also bear in mind that if the bag is lost or stolen and thus never recovered, at 21 days, up to a maximum of EUR 1,410 will be paid. Anything for interim expenses will reduce the EUR 1,409 by the amount reimbursed.
If you absolutely must check a bag, do remember to keep the first 2-3 days of clothing in your carryon. That will eliminate a lot of stress and running around prior to meetings.