Add an odd time signature and "free time" in Musescore

In Percy Grainger's "Lincolnshire Posy" in Movement V ("Lord Melbourne") there are a couple spots that I'm wondering how I can recreate it in musescore.

1. "Free Time"
   
   Would I just count how many beats are in this long measure and add the notes like that? Or is there a way to do a cadenza style thing in musescore?

2. Odd time signatures (1.5/4 and 2.5/4)
   
   So I know for 2.5/4 you can set it too 5/8 and for 1.5/4 can be 3/8 when I try to change the display of the time signature I get 25/4 or 15/4 and the decimal does not show up, or the 1/2 after the 2 or the 1. How can I set it where it will show up properly?

Thank you,
- LK