I found and looked at several of the schematics on the VT52 site which use the 26 in a preamp circuit.
Several of the circuits look interesting and are simple enough to try out. Two of the circuits used RC coupling off of the 26. The third used
transformer coupling. All of the 26 circuits were running with 8 milliamps of plate current. which would be about right for a 26.
Any of the 26 RC coupled circuits could be transformed into a transformer coupled output type circuit--- though you would want to then calculate the resulting gain structure (assuming a step down small signal OT) and make sure it is enough for your needs.
the plate choke does not need to be rated at 20 mils--- remember a lot of times builders will use parts that they already have--- this 26 tube across the several schematics shown is running at 8 mils--- a good 10 mil plate choke would work fine. We have some 10 madc chokes in the 275 to 300 henry range.
If you want to transformer couple--- a 15K B7 would provide a sufficient real world load impedance for the 26 to work into very well.
Starting out--- I would try one of his RC coupled circuits--- and maybe use an input trans with a volume control across the secondary.
MSL