I don't have the room for guttering but since I lost a whole pea crop that failed to germinate and rotted one very soggy march a few years ago, I always germinate them between sheets of wet kitchen towel under upturned seed trays (without the holes). You need to keep the paper quite wet because the peas absorb a lot of water but after three or four days, they will all have the finger of germination showing and can then be sown in the trench as per usual. This will also help to identify the duff ones. I've found this cuts at least a week off the time before they appear above ground and because thay are already growing, they won't rot if the soil is a bit too wet.