I am heavily considering replacing the lower spark plug tube O-rings. I've been researching heavily. There is a part, however, that I am a little uneasy about... marking and then pulling the timing belt off to release the tension for when I remove the rocker arm assembly.

Before removing the rocker arm assembly, I suggest removing the timing belt off the camshaft gear. This will help relieve the force pulling down on the camshaft gear end. Paint a line from the cam gear to the timing belt so you know how to realign the two parts later so your cam timing is not out synchronization. To remove the timing belt, on the cam gear end you will find an adjustment nut (14mm), which you want to loosen 1 full turn, push the timing belt on intake side inward, then retighten the adjustment nut snug again. This will loosen the timing belt enough for you to slip it off the cam gear (after your mark the belt to the gear for later reference). It may still take some force to remove the belt.

After the timing belt is marked and take off, I can proceed with removing the rocker arm assembly and replacing the 0-rings. Then I'll replace the rocker arm and then slide the belt back on making sure to align the marks on the crank...do a valve adjustment and replace valve cover...

Questions are ...

1) I've never messed with the timing belt and am a little worried about getting it back on and set with the correct tension. Is there a special tool for this.