To help answer some of the recent questions posed in this thread, you can use an app that I wrote to draw graphs of levodopa equivalent plasma levels during the day due to different drug regimen. This is based on the pharmacokinetic properties of the drugs used and the idea of levodopa equivalent dose (e.g 100mg of levodopa/carbidopa is "worth" approximately 5mg ropinirole).

Parkinson's Disease Measurement: PwP, surveys, trials, analysis

Unfortunately, I've not been able to deal with Rytary within this framework. But, you can approximate one Rytary pill with four suitably timed and sized L/C IR pills. See,

Approximating the pharmacokinetics of Rytary using IR C-L

You're right the smoothing role played by ropinirole CR (Requip XL) is due to its longer half life.

John