Where can you get Vass, G&G or C&Js (I presume you meant handgrade) for $600? Are you talking about new? Thanks.
At $500, I'm realistically looking at Carmina and CJ benchgrade.
Black shoes were traditionally the accepted color for blue and grey suits, but since the late 90's that has been relaxed and now brown shoes are much more common.
I'd encourage you to look into a pair of brown shoes- Allen Edmonds has frequent sales and you can buy second- quality shoes with minor defects for around $160-$200 during their sales. If you are building your wardrobe this is a great place to start.
Note- Be prepared to "zero in" on your correct size for each last and if buying seconds you may have to return a few duds. Shipping in the US is free both ways.
I was just researching side-tabs adjusters for a suit I recently commissioned. I fluctuate in weight 20lbs throughout the year so it gets annoying!
I'm in Australia and a quick googling shows that Allen Edmonds aren't stocked in stores here, which is a bit rough. But I'll keep at it!
The suit is the only pair of trousers I own with side tabs and I love them. I can wear them all day with braces in case they decide to sag and they are delightful. I wish all my trousers had them!
You have one of the best manufacturers of boots in the world in your country (RM Williams). Why not make an enquiry with them and propose new lines of oxford shoes?