Question for the OP - Is this the June 10th annular eclipse and (looking at your address) are you planning on this flight taking place over North America - where the eclipse is visible at sunrise?
If that's the case if side slipping/lowering the into sun wing is there a possibility you can ask the operator of the flight if it's possible to displace the planned track further to the north east than the one you have planned at the moment in order to get the extra solar elevation you need?