The $150 starting bid likely has more to do with the minimal views than anything else. Most people use the mobile app to search for specific things, and aren't even going to click on something with that high of a starting bid. If you had started it at .99, you would've had a ton more views. Of course, you may not have gotten $150 either. Although my experience is that if a bunch of items are selling for $125, and a seller puts a starting bid of $89.99 on a similar item, I'm far more likely to get it for $89.99 than I am $125.
For your high value cards, a BIN and offering a best offer is the best way to go on eBay. Won't sell as fast, but you'll get what you want out of it. You can do a quick scan of other completed sales to get a good feel for what the cards actually sell for.
If you're going to do an auction, start a 7-day auction on Sunday evening to end the following Sunday. Auctions that end on a Saturday don't get as many views. Hope this helps.
Always looking for baseball variation/error cards and anything Garrett Whitley or Ian Anderson