That’s the upper end of the target range the Dash system permits (for US readers, it’s 200mg/dL and 3.9 is 70mg/dL). I consider these values extreme. The last discussion I had with my endo he said that he doesn’t normally want people targeting below 6.7 (120mg/dL); this arose because my target is 4.4 (80mg/dL). Your target seems reasonable to me but, given that you are a new user of the system, your endo may disagree.
I think the “correct above” figure will cause problems. It’s close to twice your target, so you will watch your blood sugar go up then end up doing a large correction unless you bypass the Omnipod bolus correction calculations. My ‘correct above’ is 5.6 (100mg/dL) - about 1 above my target. The ‘correct above’ avoids repeated micro-corrections when close to the target, for that to work I would say it needs to be at least 1, maybe 2 (40mg/dL) higher than the target.
The ‘correct above’ just causes the Omnipod to not suggest a correction. You can set it to the target - i.e. 6 in your case - and just ignore ridiculously small corrections. I think if my target was near 8 (140mg/dL) I’d want the correct above to be the same, but that’s me - all my settings are very aggressive.
My feeling is that it is something you want to discuss with either your endo or a diabetes educator who is familiar with the Dash system. You may be able to get a telephone or zoom (etc) appointment with an educator at short notice.