Mesh seating on recumbents seems to be a good idea, both for some sweat relief and a degree of rain disposal. I've no idea on the comfort aspect of that though, never having ridden one long enough to find out. There could be a performance hit too, if the support isn't firm enough.Sweat
My main purpose in getting an ebike was two fold. a) to allow me to cycle everyday which I'm pretty confident it going to help me achieve and b) do that commute with out sweating buckets. So far so good on that front though I find that my back get a bit sweaty from the seat but that I'm fit for work with a quick wipe off which is far from the case on a ordinary bike. Apologise if this is too much information.
Wet
So what's it like lying down in the rain? No so bad, I only have a rear mudguard so I do get well sprayed but with decent jacket and waterproff trousers I stay reasonably dry even in a downpour. You do get some pooling round the waist but it seems to be ok if you hitch your trouser up high enough.
Sigh... I'm so unfit. I'd give it a test run. There great fun and I wouldn't want to think I put you off because of my poor pedalling skillsoh, i see..
the fitter you are, the higher your speed and for that the more you will benefit from lower air-drag
for my speeds: this are also legal in da Schweiz
this are the speeds without motor
with motor i think nearly any kind of speed with nearly any bike can be reached