george53,
First thing you need to do is realize that Uncle Kevin is a salesman, and a business owner. That doesnt mean that he is dishonest, which I dont beleive that he is, but he does steer his customers to what he has on hand. And that isn’t always your best option.
Personally, you couldnt pay me to put a Chinese or Russian 5AR4 in anything I own. They are literally a last resort choice. Spend a little more and buy yourself a genuine Mullard GZ-34. It is equivalent to and a direct replacement for 5AR4, for your Prima Luna. They are both 5 Volts, 1.9 Ampere, Half indirect rectifiers. Then your good to go for the next ten years.