IMO it would depend on the game settings and if you plan on using diplomacy as a front line tool or a side tool for you race.
-F WM like any -F is great out the gate so would work well in tiny/small universes and resonably well in medium. Diplomacy would be more along the lines of leave me alone or your next style or give me this or your next style since you have to grow fast to get the territory you need to keep your race alive past mid game. Wars should start before 2420 and aim for 3.5 tech minimum.
HG WM is needs to be more diplomatic in their games then straight out fight. Your planets are vulnerable and you will be looking for a SD or IS to get mine layers from as a close ally since your planning to fight more mid to end game rather then early. War should still start 2430ish to get territory before your race advantages are done in by your disadvantages but your planning to use BC Jihads and DN's mid game for your primary war fighting which even in end game are very dangerous designs. 2.0 tech can survive but 2.5 tech suggested if regenerating sheilds are used.
HP well you just throwing away everything if your playing WM HP since you wont beable to feild the needed fleet till into the 40's to go offence but dont have the defences to keep your few worlds if someone attacks you. Dont play