Has anyone replaced tubes in Aesthetix Rhea ?

After several testing sessions I would also like to share a solution I am very happy with. Minimum noise, excellent transparency while keeping a full bodied sound with huge soundstage:
Single Ended stages (2): Telefunken ECC83 smooth plate
Phase converter stage and amp stage before 6922 (2): Telefunken ECC 83 ribbed plate
Buffer: Siemens ECC88 gold pin.

When I first started to play around with the Rhea, I liked the all Telefunken route. It was good enough to convince me that I needed an IO which I did purchase.

I did find another tube set I like better and it's cheaper to boot. In the first gain stage (v1 & v2), NOS EI's from vintage tube service. In the second gain stage, GE black plate 5751's and for V5, a Telefunken 6DJ8.

Dear Sbrown, Was just passing by and saw this old thread. With regard to your chosen tube complement, just be certain that the "second gain stage" does not lie within the RIAA network, because the electrical characteristics of the 5751 are not identical to those of the 12AX7. Thus using a 5751 would alter your RIAA correction. (But perhaps this has had a sonically pleasing result, by chance.)

Aesthetix can tell you whether this is an "acceptable" tube substitution.