After hunting South Africa this year I plan on sticking with the same arrow for Michigan deer.
92gr brass insert
150gr or 175gr VPA 3 blade broadhead
Total build up weight...462gr (150gr VPA), 486gr (175gr VPA) with 20.4% and 21.8% FOC respectively.
These combos out of my M355 made two holes in three Impala, warthog, zebra, and Kudu. If it's not broke don't fix it. I've not chrono'd these out of my 355 but I'm guessing based on passed experience that they are somewhere between 310-325fps. I'd rather go heavy and have less noise/shock and stress on the bow than go light.
Not a fan of bullpup designs as the trigger linkage is always an issue. I really wish Excal would make a bow that has as good of balance as the 355, the power stroke of the M400-405, and the ability to throw a 475-500gr arrow at 380fps. Now that would be a magnum! And as flat shooting as all of those itty bitty 375gr arrows.
I've gone down this same direction lately. Some differences. 92g insert, 20" STs, Blazers, 170g (FOC) or Xbow Tricks(using 175g since I have them , but would choose 150 version for this insert wt). Arrow wt is 485-491g. actually need to test with 100 & 125g broadheads but sure like the feel of this extra wt. Use this with BD400.
M405 - 18" STs, Blazers, 50g insert, same broadheads (420g). M380 - 18" Zombies, 26g insert, Blazers, same broadheads(390-395g).
I will likely limit my usage of FOCs to heavier arrow setups and higher energy. I'm slowly migrating towards med wt arrows 425g- 490ishg. 20" arrows seem to have flatter trajectories than 18".
My guess for an ideal arrow (for deer) for a 400 or 405, 20" Tactical Tapp, Blazers or SK300, flat plastic nock, 92 or 110g insert and one of the G5 broadheads or 50g insert with 150g Xbow Trick or VPA, or 26g insert with FOC or 175g Xbow Trick or VPA. Just some thoughts.
For shorter rail length than 400,405, the above with 18-19".