how much rest for 8-10x300m @ 800m race pace?

If you have ample leg speed velocity....1:30?

We do this exact workout, at training.

2-3 minutes rest, usually we start at 100m after the start line, walk the 100m back to the 300m start, rest for 30-45 more seconds or so, and then go again.

This workout is though, I hope you have a great workout!

Depends on what time of season. Early season I'd take long rests (I wouldn't actually do this workout early season). Late season short rests. 90 seconds would probably be good, though I'm not really good at judging this as I don't do this sort of workout much. 2:00 might be necessary. Just be sure not to run the first ones too fast.

We did 8x300 (3) Windy and rainy.

Times were,

41, 41, 41, 40, 40 40 39, 39

Guess my Pr's

with long breaks like this, your PB could be anything.

1:57?

Pr's should be PRs since we are talking plural.