I just built this little guy for you, Hopefully this will work. I'll get around to making a tutorial video for it later this week, but i'm sure you can figure it out (there's a small help section when you click the ? and then click on anything orange).
It outputs OSC strings to Resolume's text blocks that you can then change the font, color, size and positioning of. Just copy and paste OSC from Resolume to Count Down.
It also sends out Spout and NDI if you just need something quick.
I also built in OSC and DMX triggers for 10 seconds and 0 seconds so you can fire off light desk cue stacks or fire off a video or something inside Resolume when you get to those special moments.
Try the DEMO out first, it's 5 min long, so set your timer or Time Of Day countdown for 2-3 min for testing, if you like it, it's $5, which is typically $20 cheap than the other plugins out there.
Hope this will get you buy for now?
https://gumroad.com/l/count_down_demo_pixel_party