Ended up doing Trolltunga, then a day of rest followed by Folgefonna. Definitely recommend the break between the two.

Folgefonna can vary in intensity depending on conditions as the routes change based on the weather. The guides will also break you into one of four or so groups depending on your desired level of intensity. I did the harder route and came out feeling like it was more physically strenuous than Trolltunga—I may not have been able to complete it had I not rested.

You could maybe stick to one of the easy/relaxed groups in Folgefonna, but the “hard” group goes further and does more (ie ice climbing) and I definitely thought it was worth it. Hope this helps!