Finally finished my Ascension Crossbow.
Below is a picture of all my loot, the killcount, and the cost for each signet.
Total Cost - 205M (going for around 280m-290m atm)
12 Primus - 9.6m
2 Secundus - 1m
90 Tertius - 45m
117 Quartus - 58.5m
101 Quintus - 58.5m
15 Sextus - 10.8m
Dragon Crossbow - 22m
16.4m in loot
About 189m for my crossbow if I consider how much I made with loot.
(both keys are 700k-800k [Primus and Sextus])
Also, here is my tactic on fighting the Legiones:
(chickens = lightning)