I don't see much difference between 25' and 40'. On the weaker signals, I only see a few tenths of a dB improvement, not enough to justify building the 40' tower or mast.
The Channel Master 3671 would be a good single antenna solution...
The two antenna option I suggested earlier would out perform by two or three dB. Receiving reliable signals from the weaker stations is my concern. I'm worried that due to the 2-edge paths, you will need to build as much margin as practical to reduce the effects of fading.
From what I can tell WJFB is broadcasting a jewelry shopping channel. WNPX is an ION affiliate and WNAB is a CW affiliate. If those are all low priority stations for you, keep the CM3671. If any of those are 'must have' stations, consider returning the CM3671.
If you use the CM3671, an Antennas Direct
PA18 would make a great preamp.