I use Toko fiberlene, which is much thicker and thus more absorbent than Swix, and on my last pass I pull a long piece along underneath the iron, moving the iron down the fiberlene when the part under the iron becomes saturated. That leaves a film of wax on the surface, so after the skis have cooled for at least 3-4 hours, preferably overnight, I need only a few minutes of scraping to get everything I can get off the skis, and then, I don't know, several minutes brushing until the bases are sexy smooth. I'll have to time it sometime. But IME, scraping is no more tedious than brushing; in fact, it seems more immediately productive to peel off visible amounts of wax, while brushing is a slower and more subtle process.
On your ski tips bouncing up, I assume you mean rebounding when the scraper comes off the end of the ski, which means your tip and tail supports are too low. My supports are raised so it takes a little force to pull the tip up off of the end support when the ski is in the vice, and even if I'm pressing hard on the scraper the tip doesn't rebound or vibrate when the scraper leaves the ski, releasing the force. I don't go overboard and put a lot of stress on the ski, and I always release the supports so the ski doesn't sit there under tension. I'm not sure how your end supports are constructed, but if nothing else you could raise your supports by putting a piece of wood between the support and the top of the table before tightening the clamp that holds the support still.
Another wrinkle: have you checked your bases for flatness? Maybe they're base high or edge high (railed) or a combination of the two. That could mean that on one pass of the scraper you're hitting one part, and then a different area of the ski the next time through because maybe you're holding or bending the scraper a little differently. Hopefully you have a true bar, so you can put a bright light behind it and check how level the base is every few inches along the skis. If you don't have a true bar, look around the house for the thing that might be the flattest; even if it's not perfectly flat, it will show whether the base is differently shaped in different areas of the ski. Here's a true bar
that's not super fancy but looks good to me. Its thinness and height will read flatness well, and it's way, way cheaper than the best flatness tester I've seen on websites, the $80 SVST world cup true bar.