I suggest you wait and hold. I understand its hard times especially when people are tempting you to sell them your D3s. At our local crypto market for example, people are offering to buy what they call paperweight Antminer D3s at $500. The sad part is some people do sell.
But don't give in. Crypto is volatile and DASH maybe up by 1000% tomorrow. Selling now would be tantamount to buying high and selling low (illogical trading strategy).
Look, everyone has their opinions on this but this advice is quite risky IMO. At current rates (DASH, daily profit, ebay market for D3), the OP is looking at a break-even to what he could sell one of these for in a whopping 600 days! And, that is with DASH price exploding... up 65% in the last 2 weeks to about $575 now! I know a lot of people are optimistic about further rise in DASH price, but in reality, it would have to go to 3-4x it's current price for the OP to even have a shot at recouping the 900 Euros he could currently get for 1 on ebay. Can anyone really say with a straight face that they count on DASH hitting $2k in the near future? As a DASH holder i would personally love that but in reality, it's not going to happen.
Also, about the other X11 coins... DASH is currently the most profitable to mine and there are only a couple others that are barely profitable at the OP's high electric rates. Half of them he would be mining at a loss. It would be very very speculative to mine any of these coins just hoping for some miracle spike in the future when he can get 900 per unit now, but maybe if he's feeling very brave, he could sell one and mine with the other?
I know it's tough to pull the trigger and sell for a loss but all the factors here point to those D3s only going down in price from here. You can't think of selling one for 900 as a 1,600 loss... you need to think of it as mitigating a loss that has already happened. Would you rather have 1,800 in your hand today or wait a months, realize mining is never going to recoup even than 1800, then be forced to sell them for 1,000 or less combined?
And, think of it this way... the only possible way to come out ahead of the 1,800 now is if DASH goes into the $2k range, right? And in that case, maybe you end up breaking even (to the 1800) or exceed it by a couple 100 if you're very lucky. Well... if you sold your D3s now and bought 4 DASH with that 1,800... you would be looking at $8k if DASH really does hit that high mark. Even if it only doubles, then you are in the range of recouping your original $5k investment.