1- If you have a powerful off-hand weapon like Orochi Thermal Capacitor, casting power abilities with that off-hand will out-dps any benefit you may receive from casting main-hand basic abilities. You are generating 1 energy per second for your main-hand while using the off-hand and around 1.4 energy while spamming basic abilities (assuming you have 40% crit). Over the course of 3 seconds while you cast 3x Mjolnirs you can gain maybe 1-2 extra energy for choosing to spam basic attacks, but the damage difference should be too big to outweigh that extra energy gain. Without such an impactful off-hand though it can be roughly equal.

2- Lady Margeret necklace is good but since Egon Pendant is mega OP it can’t compete really. But margaret and spectral essence necklaces are both 2nd best options after Egon.

3- I have seen many people claim Harmonisers are BIS but never seen the math calculation to prove it to be so. It’s easy to calculate the concrete dps benefit of Third-Age or Flame-Wreathed but very hard to calculate Harmonisers because you need to 1) Make a probability distribution to lay out the expected time of combat a generic pistol user will spend having matched chambers of each color (e.g. 30% of combat is spent in white matching set, 10% is blue etc.) 2) you need to calculate the expected probability of upgrading the color during the 3 second window you have a matching set and then calculate the chance of upgrading on the 1st second, 2nd second and 3rd second respectively 3) then you need to account for the dps you technically lose for upgrading the color. because you just lost a portion of your blue set and replaced it with red now. while you got a full 3 seconds of red, you lost 2 seconds of blue time you would normally have 4) then you must account for the chance of double-upgrading (i.e. from white to blue and then to red) 5) when you finally figure out the new expected distribution of time that will be spent in each color you may now calculate your expected DPS gain. — Or you may compare dummy test results between 2 pistols of same item level and suffix but then you need like a 1000 tests to eliminate chance factor.