Thanks Dennis,
I think you are probably quite a bit faster than me

The Cicerone guidebook gives 2h20mins from Roussies to Pachnes summit. I don't know if this is calculted for a person with backpack or only a daysack. But for me, the Cicerone time estimates usually (not always! Sometimes i am faster) work out. For instance, their estimate for the ascent from Katsiveli (also 2h20 mins), which i did in 2018, was spot on for me, almost to the minute.
If the section to Zaranokefala is only 2 to 2,5 hours like you say, there would be plenty of time to reach the summit and afterwards camp at the spring. Depending on the time, i would even consider to descend to Potamos mitato to walk Eligias gorge next day. If i can't make it to the mitato that day i will go down to Aradena next day.
I prefer the route west of Mesa Tourloti because it looks easier to navigate (no sinkholes).
Cheers,
Sebastiaan