Bridge wing pickups are sensitive to pressure. I once got a Shadow SH-950 (clone of the Underwood with a bit thicker ceramic element) and it needed some force to put it into the bridge wing. Sounded compressed but I thought it is the sound of the pickup. Years later and after changing to other pickups, I removed just a very little bit of wood with a few light strokes of a fine file the pickup slides it very easily and was barely held in place but the sound was so much better that I might not have tried something else then.
Position is important too, depending on the construction of the pickup. So you might experiment with that too and mark the position if possible on the pickup.
I only played one bass where the Realist sounded nice yet. In general I don’t like it because the high kids and highs get lost and intonation is hard to hear. The Lifeline is also dark, but not as much as the Realist. It is easy to reduce frequencies on EQ if there are too much, but they are barely there there is not much you can boost (and get a lot of noise instead).
The Realist is also not good if things get loud.
A better alternative to the Realist is the Shadow SH-965NFX. More upper frequency content, could be used with one or two sensors, but needs a common lithium cell as a power source. Battery holds for a long time as long as you remove the plug from the battery adapter (this is the power switch).
Less punch pizz than a bridge wing or adjuster pickup, but very nice with the bow. Maybe too less punch with synthetic core strings. The impedance buffer is built in, so that’s the reason for the battery and the output works with any amp. The signal is a bit quiet.
The Full Circle is good if it gets loud, punches through a big ensemble, maybe not the best soundwise in a small quiet ensemble.
There are two potential problems with it. One is the sound that changes quickly by just a little bit of rotation and the second the lifetime of it that can be reduced or terminated mostly by impact in the bridge (most commonly during transport) or maybe also simply by having it mounted under the pressure of the strings. Five years could be expected, some use the Full Circle a lot longer. A better alternative but more expensive is the Japanese Yamahiko that you need to order from Japan directly. The FDeck HPFpre is a good preamp for that one too.
I think the Full Circle and the Yamahiko are the most feedback resistant pickups.
