I gave up on the Selle Royal Drifter saddle. Got an Ergo "Classic" instead.
 

After riding a longer time with the Drifter saddle, I still had pressure and discomfort in the crotch no matter what angle I tilted the saddle. I realized that the fore-aft dip in the saddle causes the nose to push up on the crotch when the springs are compressed by your sit-bones as you ride. I bought an Ergo noseless saddle, the Classic vinyl-covered model called "The Seat", which on Amazon I found for about half the price of the Drifter. It takes a little while to get used to the shape and firmness, but this saddle grows on you as you ride it more. I like it now, and there is no crotch discomfort at all even after several hours of riding. Some people reviewing The Seat say they don't like it, hate it, find it very uncomfortable, but most people give a very positive review. If you are having trouble with the saddle on any bike, give "The Seat--Classic" a try.

I also modified the original Schwinn Loop saddle in a way that greatly reduced the crotch pressure. Using a high-temperature hot-air gun such as is sold in hardware stores for such things as softening old paint to help scrape it off, I heated the cross-beam under the sit-bone area of the saddle. When it was pliable, I curved the rear of the saddle to create higher sides and a deeper dip in the midline at the rear where you sit. Holding that shape by hand, I let it cool under running tap water. Then I remounted the saddle on the bike. This made a big improvement but still not as good as "The Seat". Before buying a new seat for your Loop, give this a try.

I just purchased this bike, love it so far. Any tips or things a new Loop owner should know?

Check that everything is adjusted properly, such as the spoke tension. Mine came with random, widely varying spoke tensions. Some spokes were very loose and others normally tight. Pluck the spokes like a harp string and if some make a dull thud instead of a musical note similar to the others, you need to tighten that spoke. Mine also came with very poorly adjusted brakes and derailleur.

Thanks for the tips. I ended up taking it to the bike shop for a tuneup. Not sure if checking the spokes is something normally done but I'll check them tomorrow.