I hope your Borneo cucumber makes it to full maturity for you; if it does you'll be in good shape with seed stocks because one cucumber can make A LOT of seeds. Right now I've got 3 Kaisers on the counter and I'm waiting for the perfect moment...
Well, there is also the matter of if I like the TASTE of the Borneo, I've never tried it before. I'm not even 100% sure it's a true cucumber (with that shape and those stripes, it looks a lot like more like a carosello, a.k.a. a cucamelon.)
And how true it is (that's one of the reasons I kept a packet back last year, in case the Borneo crossed so heavily with everything else it became junk.)
Cucumbers can THEORETCALLY make a lot of seeds, but it is always a matter of pollination rates. I only pulled about seven seeds from the two or three Brown Russians I seeded last year (then again, they were really tiny cucumbers, which was actually HOW they wound up as seeds, they were too small to be worth peeling and eating).
And the Russian netting having those little unfertilized ends is a bit worrying. As far as I can tell from pictures, Russian netted is supposed to be a spherical cucumber, so it should HAVE a long bit poking out of the bottom. But what else could they be. They're the wrong immature color from Brown Russian (those are pale green to white to yellow to brown, these are dark green to start), and the Sambar are supposed to have stripes.
On a side note, someday I'd like to try my hand with a little cucumber crossing. I'd like to cross a spherical cucumber with a gherkin-type cucumber (that is, one that makes a lot of very small fruits rather than a few large ones), to make one that has both. Think I'll call it "Lantern Chain"