Hey Roadster,
About your energy boosters....
I use a combination of Powerade and Gu for my races. Gu every 45mins or so and Powerade gulps when I can (About 3.5 litres for 94.7). It seems to work OK, I can't say I feel like Lance on the climbs when I use it but its better than the Energade/Corn Syrup combination I used to use!
Before races I also have a good breakfast. I find I'm up fairly early on race day (Butterflies flying formation in my Ascending Colon!! 😄 ) so I eat as much as possible, low fat... One egg (Protein) about four slices of bread with jam and a banana or two. I supplement this with about 500 ml Carbo drink (Powerade or Energade Megalode). No tea or coffee as much as I'd like to, or I'll be doing some unscheduled pit stops. I make sure that I eat at least 2 and a half hours before my start time. Also a banana while I wait at the start helps.
Another thing I found which may help is a product made by PERC called Carbo Boost Stack. Its a carbo drink with Creatine all in powder form. You'll have to check the effects of creatine on your system on long rides before you try it in a race. Many people complain of cramps due to Creatine, but it doesn't affect me this way. I also only drink (250ml) in the last 30-45mins of the race when I may need the extra boost in my legs.
I've tried the energy bars available but they only seem to give me a boost and then drop me to below the energy level I was before I ate it. So I've given those a miss.. :P
Hope this helps in your search for spare muscle glycogen! 😉