Have no idea of your setup or health/fitness etc , but why chop it up ?
If you have access to horses , you could mix some crap with it , pile it up , leave it for 4 or 5 days , then turn the heated heap into a new heap , leave another 4 or 5 days till it heats up again , then turn the heap again. 4 or 5 turns and you have compost !
Anyway , if you must chop it up ? , don't chop it too fine as it will most likely form a dense clump that won't rot .
3" to 6" is small enough , and mix it well with manure (if poss?) and waste veg , as well as grass cuttings . Soak the straw before you add it to the tumbler/heap , but after you chop it up.
Water will do for soaking , but as much pee as you can produce will really boost the speed of breakdown . Take care if you are on medication though , as some meds pass through the system and can be dangerous in compost , if it doesn't heat up enough to break them down !
Good luck !