G'day george ...... good advice from the blokes, and there r other options just to make ur final decisions even more difficult!! ... ur power supply board can be selastic glued via the base of the caps to a square of ply & attached to some lengths of wood or alloy struts across the width of ur case .... this is so u can still remove ur base plate to get access to the solder side of ur boards if need b.
Most of the commercial cases such as the jaycar come with drilled gal steel U struts 4 the frame anyway & they are threaded on each end- dont know wot uve got but if u have this style there r extra lengths in the package. U can use these to do the above ... the ply base PS platform will be captive by the U sections on 2 sides front to back, & screwed in from the o/side of the case to anchor them. This is the method Ive used on my ol 55 & a thick cable tie each side of the PS platform just in case the screws into the ends of the U sections from the o/side decide to break their moorings.
as for cable .... u can source High Conductivity/varnished OFC copper cable from ur local motor rewinder .... & use it every where.... there r threads for tara cables as previously mentioned .... its done using 18awg & u'll find an equivalents table at the TNT audio site with wire diameter in realspeak ie metric. My preferred speaker cable is single 12awg = 2.053mm dia & a very interesting site is
www.anticables.com ... u can make these up ur self 4 next 2 nothing using enamelled copper HC/OFC wire. U can also get urself a roll of 18awg = 1.024mm dia & roll ur own taras!! ... same for internal wiring of the amp ... my advice would be to hard solder the selected solid copper cable runs to either PS board or amp boards & spade connect at other end .... so u can dismantle for mods/repairs .... same for ur speaker terminations to ur chassis.....solder to the back & spades to ur boards or vice versa & drill a hole in ur boards & solder rather than use the male spade supplied.
just remember there is no definitive science involved with spkr cables & IC's just a few working principles....and EVERY commercial manufacturer has a profit driven agenda to pursue ... so its wot works best 4 u in ur situation .... & budget
hav fun with it .... now if anyone wants 2 send me lotsa fresh $$$$ bills I'll reveal my recipe for the most sonically devastating pre to power etc IC's using air-cored DSE co-ax cable!!!??? .... but ye don't use the centre-conductor, just the shield!! .. and decent RCA's of ur choice
cb