It's awesome to see how well these cards appreciated in value. Dug out my collection a few days ago. Sitting on 50 base 5 silver 2 black and a handful of minis. I guess I'll send that couple to HGA while waiting on BGS to allow submissions again. 
Those are good cards to have.. Hotbox silver especially. i would wait for PSA if you are sure they will grade well. Maybe send in through a card shop for best rate.
Yeah I've got a guy I send to that submits them. He's got some setup with different color lights and cleans them up and videos me about what he thinks it'll grade. I've only got 9.5s back from him and the others he rejects just cost $3 for inspection. I do think HGA will stick around tho. I like them at least with the color match. Happy collecting!
Also there's a black mini x for auction on eBay with no reserve that started at .99 cents. This should be fun to watch.
https://www.ebay.com/itm/234063616072
Wow a /100 mini x. Auctions high risk with recent cool down. PSA 10 mini card sold for 240. The word hasn't gotten out on the rarities so folks only want base card. Id be surprised if it goes over 600. Easily a 2500 card.