Hi use the R2R, the other config that Jerry is referring to is the upgraded Amanero version. Don't think anyone has compared the two, but given there is not much cost difference, go R2R. Get DSD 256 at a minimu. 512 is optional. Don't get a preamp if you prefer to use an external one.
For stock tubes, don't get the EML recti - get the KR 274b. Don't get the 101D replicas as stock tubes, instead ask for the KR 242. If they don't give the 242 as stock, buy those separately, and ask for the amount of money of stock tubes to be deducted.
If you don't mind having 2 or 3 differing flavors of tubes, get the KR PX25 and some good 300bs of the market (Elrog, Tak, depending on your budget). I know they offer KR PX4 as stock, but not sure they offer the PX25 as stock.