Hi Smileymiley,I see you have the PS 08 running you radio and I think your asking would it also run a 203p.I just googled that amp and it needs at least a 10amp power supply to run it.So the PS 08 is a bit under gunned at 6A-8A,But look around as you can find some reasonably priced supplies.Google TLC electrical as there’s most probably one near you or they can deliver,I think a 20A supply from them is about £40 and should run both your radio and linear.Just have a look your be surprised.
As for the order of radio equipment inline -
McKinley - Amp -SWR Meter -Antenna tuner - Antenna.
Sorry I went the other way but their both in the right sequence.
Not sure what Zetagi tuner you use but bear in mind if it’s one of the smaller MM27 they max out at 100 watt,That 203 supposedly does 200 watt ssb.Easy does it…lol
Hope that was some help.