Nice to hear you got out to enjoy the Simplex +, especially with the 5 x 91/2 coil. I use my Simplex with the standard 11 inch coil in wide open parks or hunting a plowed field, but my other Simplex +, that's part of my Daily-Use Team, keeps that elliptical coil mounted full-time.
Generally I use Park 1 for most of my Coin and Jewelry hunting, unless there is a lower amount of trash and then I'll either use the field mode or the beach mode. Every mode on each Simplex + has the sensitivity set at maximum. I never start out and see if I can increase it, I always turn my detectors on and have it at maximum and then I reduce it only if I need to for stability. Seldom do I have to drop more than one or two bars.
I enjoy that coil for similar reasons to what you stated, the detector being more stable and less EMI, plus I get very good audio and visual Target responses. I have both of my units operating with the 2.77 upgrade and I have not had any issues at all. I'm curious, why you went to the 2.78?
It looks like we might have four days of pleasant Fall weather remaining before we crash into low temperatures and a chance of some snow this weekend, so I scouted around this afternoon. I found the owner who just bought two lots and bladed them so all the weeds are gone. I got the permission to hunt it and that's where I'll be tomorrow. Likely using Park 1.
I hope you can get out some more with your Simplex and the new coil. It's a very pleasant and enjoyable detector to use.
Monte