There are Loctal equivalents for 6V6, 6SL7 and 6SN7.
7C5, 7F7 and 7N7.
Much lower cost, nearly identical ratings. These are 6.3 V tubes not 7V,
the 12 V equivalents are 14C5, 14F7 and 14N7.
Should run well on a DIY 35 board with sockets wired in, reduced plate voltage (250-300VDC max) and output power (10-14 watts).
/ed B in frugal frozen NH