Good luck! We're in CO, too. Dd11 had a 504 in 4th grade and we then opted out of it and wrote the extra time & quiet testing environments into her ALP instead. I think that we were on shaky ground for those accommodations, honestly, and I don't expect that she'll have them beyond middle school (and we haven't sought them for things like talent search testing). Dd's accommodations were based upon a dyspraxia and SPD dx at age 7.5. I don't know if either dx is accurate although SPD may be.
The accommodations you are asking for sound entirely reasonable for a dysgraphia dx alone even without the dyslexia dx. Who initiated the 504 process? I'd expect that the school will be reasonable if it was their idea.
