Thank you sirs!
Got the power transformer (Hammond 370FX) and chassis (Hammond 1441-32BK3) from Mouser.
The output transformer (Toei OPT-20S), rectifier diodes (UF4007) 1/4" jacks (Switchcraft), potentiometers (Tocos Cosmos RV24YN20S series), high-voltage switches (NKK M series), knobs, tube sockets, IEC connector, pilot light holder, and bias test points are from Akihabara in Tokyo, Japan.
The Standoffs are from RS Online, measuring 75mm x M5 threads for mounting the entire thing onto a head or combo shell, and 20mm x M4 for holding the Lazada-sourced eyelet board onto the chassis.
I had to special-order the 120pF and 250pF Silver Mica signal capacitors because I couldn't seem to find anything that's rated for at least 400V locally. These were ordered from element14.
All the remaining resistors, capacitors, switches, potentiometer, fuse holder, wires, screws, washers, nuts, bolts, and ring terminals were sourced locally (Ohms, Deeco, Alexan, etc.). Note the Orange Drop 716P capacitors rated for 400V, gotten from epektos if I'm not mistaken.
I'm still thinking of finding the correct incandescent lamp type for the pilot light, but right now I'm pretty satisfied with two diodes in parallel plus two current limiting resistors, with minimal flickering.