Pricing for Vintage Cards Question

[Bretsky]

Hello, I've been getting more into vintage cards again as my Dad has started collecting the cards from his youth and already has a few 50's sets together. My collection over the past could of years has been mostly modern where pricing is basically guided by Ebay. We have tried to do the same with the vintage cards along with pricing from SMR as we have a PSA membership. I noticed a lot of people use VCP to justify their pricing in BST section.

My question is what is the more accepted assessment of values for cards? SMR seems relatively in line with Ebay but also seems off when it comes to more popular players and cards (undervalues) and maybe overvalues others. I checked out the VCP website and it looks interesting but a bit expensive compared to just using Ebay or SMR. I like that it takes into account auction house pricing. Is SMR a decent guide to go by or should we pay the money to try VCP? Also does VCP have a few that looks at all prices for the cards in a set based on checklist like SMR does? Thanks!