If budget is very tight... it make sense to do some compromises, but still go for a Threadripper. You will end up in the end with much better deal overall. Same performance in one box, better electricity usage, more memory (and easy upgrade path) and even better resale value.
Here are some suggestions:
Cheapest X399 board is good to go (Asus Prime, MSI plus,..)
Buy only 2x16 GB. Buy more in future when you'll need. If not, 32 GB in Threadripper is less than 2x 32GB in two Ryzens. Good & Fast 32 GB of DDR4 memory is 350-400 euros. With 2 Ryzens, that's wasted money.
You will save on SSD, cooler, PSU and Case ( 80 + 130 + 100+ 100= 410 euro saved).
Ryzen 1700 costs tiny under 300 euros, Threadripper 1950X costs 900 but I've seen online price as low as 800 somewhere. But let's use the 900 price.
The cost difference between two Ryzens and Threadripper would be would 200 euros in favour of Threadripper ( 800 saved minus 600 CPU cost difference) for 32 GB systems. It would be 600 !! euros in favour of Threadripper when you'll need 64 GB memory, which you eventually will, it's very easy with Corona.