Just remember: A cheap price tag often means cheap materials, when it comes to brand new saddles.
And I hate Tacky Too pads. I don't think they conform to a horse's back correctly. My personal preferences, I guess. I feel like the pad looks awful tight on your horse's withers in the second picture, mammakatja.
OP, if you are on a tight budget, I would recommend you look for a used
saddle. One that is a quality name
with quality materials. You asked about Lynn McKenzie, and she has great saddles. Examples: Billy Cook, Triple Creek, Caldwell, Tex Tan, Hereford, Circle Y (older Circle Y's are honestly better quality than newer ones, I think).
In general, the vast majority of barrel saddles (especially round) will be 25 pounds or lighter.
I myself have never seen a Rider's Choice saddle in person, so I can't comment on them. It sounds very similar to what Corriente does.
For saddle pads, my favorites are 5 Star and Impact Gel. Spendy, yes. Worth it? Yes.
Impact Gel doesn't have a perfectly rounded-looking pad but they do have one designed for barrels. CONTOUR 100% WOOL Pad.
5 star has a rounded pad too (click on the pictures to see it) Barrel Saddle Pads - 5star Equine Products