Last 4 weeks before l'étape

Training
1

First time doing l’Étape this year and what a year to do it. I am getting nervous as we approach the event. Training has not been on the ball but not awful either. 2.9W/kg at the moment and I need help reviewing the last few weeks and my prep leading to the event. My goal is to finish and I start at 7AM.
Bike: Canyon Grizl CF SL 7. It’s got an 11-34 cassette and I am thinking of putting an 11-40 on it. Thoughts? A few bike shops said it could work.
Current fitness: did a 210k ride a few days ago in 25-32 degrees celsius (77-88F) and although eating was a bit challenging and so was the heat, I’m pretty sure I consumed 100g of carbs an hour (gels and drinks). My performance wasn’t great though. I’ve done a few 100km+ rides over the last few months and my TR FTP has consistently increased (190 ish in December to 230 now and TR predicts 239 by the event). Never ridden more than 2300m elevation in a single ride and there are no mountains where I live. I train in the attic (35 celsius / 85F) with the fan on for this week. I feel like I consume a lot of water and I don’t know if refilling will be an issue on the day.

Plan for the next 4 weeks:

  • this week: 9 hours of riding / 440 TSS (2 SS sessions, 1x3 hour outdoor ride and other endurance sessions on the trainer). 6 sessions for the week
  • next week: 12 hours training / 540 TSS (90min threshold, 90 min VO2 max, 1x3 hour outdoor ride and other endurance sessions on the trainer
  • third week: 5 hours / 350 TSS (60 min SS, 60min VO2 Max, 60 min threshold, rest is endurance)
  • last week: 2 hours (2x45 min threshold + endurance).

My plan really is to map all the water points and try not to stop for more than 20 mins on the entire ride, ride up croix de fer and Telegraphe at 160W and only push later on if I feel like I can. Not sure what I’m really asking here, just a bit nervous about it all. I am interested in gearing and training advice though - most people seem to recommend 11-34 or 11-36. Makes little sense for me to move to 11-36 and I am wondering if 11-40 is the cheat code I think it is. I am not a punchy rider - I do best holding steady around 75-80 RPM.
Thanks