I have been using FL Obsidian merino pants with merino under garments for some time, but I also went with a couple pair of Sitka Apex pants. They also seem to be ok with merino under garments.
I just bought some Eddie Bauer guide pros. Gonna test those and the KUIU guides this weekend in the hills of PA. 85-90 degrees should give me a good idea as to which pant breathes the best. I really like the SG De Havilland’s but I just bought the Attacks for considerable cheaper when KUIU was running a discount on them.
I feel like somehow the Kutanas are still under the radar. Size up, I wear 34 Wranglers and 36 Attacks but 38 Kutanas. I have a pair in Loden and Valo now, got the Lodens hemmed for backcountry wear (mainly to help prevent them getting wet when wearing crocs around camp) so they are now 38x31 and weigh 13.9 oz, but the material is tough as nails and the hip vents are awesome.