Actually the higher the mag the more critical the external lighting becomes, now 1x isn't going to make a hill of beans in difference but if you have or used a spotting scope you'd know more mag needs more light.
I have had 40mm, 44mm & 50 mm conquests the only positive difference the bigger objective had was FOV. I found no better twilght performance with a 50mm vs the 40mm. Negatives such as higher mounting, scabbord issues, etc IMO outweigh the positives of a larger bell (objectives). For biggame needs the 2-3x to 9-10x x 40mm is my choice. LR target &/or varmit I see the need for higher mag.
Our big game hunting hours are 1/2 hour before and after, no problems with my 40mm zeiss's.
One thing to add once you've selected your scope make sure to put on quality mounts. Talley or Warne would be my choice. However I've had good results in the past with Leupold Dovetails as well.
Good luck