In terms of levels, you'll be in the way at less than about FL80 in a lot of that airspace, so yes, you do need to climb to FL90 or FL100
Ok, so basically, you cannot fly IFR through controlled aispace without conforming to the airways/ATS routes and their lower limits?
Bear in mind that airways levels are always round thousands (e.g. FL90 for that route).
I thought that below FL245 you should fly at a level applicable to the semi-circ rule? If not (and the airway is available in both direction), how do you know what level is available?