Investigating Balanced Tube Preamp

[brxl]

Hello all,
am new to the idea of using a preamp, always thought I could get away with a volume control on the source and directly go into the power amp. However, lately I dabbled using the preamp section of a Yamaha AV1 receiver between source and power amp (ARC VS115) and it has a bit more "foundation" with it. SO now I am infected with the idea of getting a balanced tube preamp and really intrigued by this chinese clone
Hi End AudioResearch ARC Tube Preamplifier Balanced/RCA IN&OUT,12AU7/ECC83+ECC88/6DJ8 Preamp DIY Kit|Amplifier| - AliExpress
There are many questions just arising from the text (it can be found on ebay as well, but the pictures on this ad are better)

Assumptions:
1) the coupling transformers are to connect unbalanced inputs and process them as balanced
2) the rectification and voltage regulation is included (board and part-wise, except the EZ90 tube)
3) hard time finding a transformer fitting the requirement 280V (two sides), this one is quite close 80W pure copper R-core transformer for tube preamp / phono 280V-0-280V +6.3V *2 | eBay
would one get away in connecting the 2nd 6.3V circuit in series to the first one to tap of 2A @ 6.3V and for the series connection 12.6V at (2A, instead of 3A)?
4)not familiar with preamp topology...no need for an output transformer???
5) a quick search would have the total cost for board, transformer, tubes at 335 US, worth it or better get something what looks like the finished (copy)?
12AU7 ECC88 Valve Tube Bile Preamp Pre amp American ARC Circuit Tube HiFi Balanced Bile Preamp Chassis shell/finished machine|Amplifier| - AliExpress
for roughly twice the price
6) I am really interested in building a kit this time (it has been a long time since I did something in the amplification world)

What are your thoughts? Have you build one of these clones yourself?

Cheers
brxl