I am about 2 weeks into riding the SLR superflow, after trying out the flite boost superflow for a month. Not sure if you are wanting to try the full length or boost version.
Before this I tried the selle italia slr boost, and had the same trouble you mentioned with it being a bit too wide at the nose and rubbing the inside of my thighs. I then went on to the flite boost kit carbonio superflow. The saddle is pan flat with a dropped nose and a very large flat area to sit on at the back, so it was very supportive for my sitbones. I used the superflow version, which has a relatively small a cut out by selle italia standards and pretty much the same size as the cut out on my bontrager montrose, despite being wider (138mm vs 145mm). The nose of the flite is slightly wider than the SLR and I still had a bit of thigh rub from it (but they may be because it was the boost version). This was the first flat saddle I have used and you have to get used to actively rolling your pelvis forward and doing more of the work to hold your posture, but you are rewarded with a lot more flexibility in terms of how you sit, allowing you to pick your own position at all times. I found this saddle generally very comfortable, but the big problem I had with it was the incredibly short rails. The manufacturer limits were only about 2mm longer than my saddle clamp, leaving almost no fore/aft adjustment.
The SLR is a lot more like the fabric scoop than you have mentioned and is a very traditional saddle shape and design. It is generally listed as a flat saddle, but has a slight rise in the rear, which is noticeable when you sit on it and it supports the sit bones well. Like with the flite, it has a very large flat area at the back which is supportive for sit bones. I have had no issue with thigh rub using this saddle, as the nose is narrower. This is also aided by incredibly long saddle rails, which give you a ton of adjustment room. I am using the superflow version as I suffer with numbess and like cut-out saddles, but I am struggling a bit with the massive size of the cut-out (up to 36mm wide) and feel the inner edges of the cut out press into my soft-tissue a bit. But then again I am still adjusting the position, so maybe I don’t have it dialled in yet.
Generally, they are very similar traditional shaped saddles, the SLR just has more of a rise at the back and a much bigger cut out. As someone who has tried various saddles over the last 2 years in search of the right one, I encourage you to ride both of them. It doesnt matter how well or badly the saddle might fit you based on design and flexibility etc, its all down to how it feels when riding it.
Hope this helps, happy riding!