VCP average for a complete set PSA 4 is exactly $6976.85.
3 months ago, Love of the Game sold the #58 Registry Set with a rating of 3.57 (
link). I was bidding on that item and I still have my spreadsheet for it and the total individual card values of it was $5100 and it sold for $5900 = $5000 hammer + $900 BP.
Therefore, I'd put the trade value on the 53 set right at $7000.
Hope this helps.