Low gearing for off-road touring

[Cyclingtimmy]

I want lower gearing for adventure touring. I currently have a Praxis Zayante 48/32 T double chainset and a SHIMANO ULTEGRA RX R8000 11-SPEED SHADOW REAR DERAILLEUR GS with 11-34 T. This is the official maximum range for this derailleur but some websites say that you can run up to an 11-40 cassette without a road link, even with a double chainset. The recommended total capacity is 39T but the set up I want will give me 45T. I would obviously also need to fit a longe chain. Does anyone know if this set up works and any other advice would be much appreciated.

[NATURAL ANKLING]

Hi,
I'm not sure if your bike will allow it but I would've thought a triple clanger would be more practical.

[hemo]

I added a 11 -42 with a road link to my gravel bike for higher gearing and it worked with no adjustment except the a longer tension adjuster on the Tiagra 10 sp GS derailleur.

[NATURAL ANKLING]

Hi,
I was going to say for OFF road touring on any bike up hill on grass you need at least a 20" 1st gear.
Touring as in bike will probably weigh 20 kgs?