help needed

[electronics technician]

i need some advice on this power supply im going to make i saw it here on this forum but im not seein it here anymore so here goes
i did some research and found thsi circuit
http://www.thebackshed.com/windmill/articles/VariablePowerSupply/TheBackShed723Reg.gif
im going to buy a dual voltmeter and ammeter with current shunt rated at 300a and 300v
i rewound a (mot) microwave oven transformer to get 27v ac and i need some advice on it thanks