Only PCB resistors exceptions are R13 (2W) R1x (1W) R3x (0.5W if possible). They are noted in the BOM also. You can buy Dale CMF55, Caddock MK132, Vishay VAR, NOS Draloric, Resista, Holco, new stock Takman REY, PRP, from the likes of Mouser, element14, Parts Conexion, Michael Percy, Hi-Fi Collective etc. There are Dale precision, Welwyn precision, Philips MilSpec/MPR24 precision low ppm sparse values on Ebay sometimes also.
Rx1-Rx4, R1,2,3,4,5,6,7,8,10,13,14 R3x are the more influential.
By measuring it. I guess you did not read the guide very well. There is a link in it. Here again http://www.diyaudio.com/forums/solid-state/23546-matching-jfets.html#post274893
Is it about 2SK170? It is GR or BL?
GR is usually low. BL should come up to 10mA.
This might show up as swedish - change to your prefered language and hopefully it will show the same products.
Vishay Metal Film Resistors - Through Hole | Mouser
Regards
See to ventilate well the back area. Besides the box is cute its also small and the output MOSFETs sinks are side by side. That will create an ambient delta more than for others. You may start at 3.1V tp1-tp2 then rest the top cover but have a clip on each c3 input side and one on the ground lug hanging out. Monitor those they slide down to circa 4V in respect to gnd clip each after half an hour. If they slide too much open and boost them up at the trimmers.