Mate, take it from someone who has been there and done that. I STRONGLY suggest you remove the sump to change the timing case gasket rather then the head. You will find that as soon as you unbolt and remove the timing case, the lower chain guide will fall into the sump... not a good thing.
Trying to get the thing back out is nearly impossible, and putting the case back on with the sump in position is a nightmare.
I suggest the following.
Raise the engine as much as possible. Unbolt the sump and drop it down. Then unbolt the timing case (Not to mention about 2 million other things that are in the way). You don't need to be too fussed abut keeping the chain in position as with the case off, you can re set the timing marks anyhow.
You may also find that once the timing case is off, the chain guides might need replacing. Also, if you are thinking of changing the cam in the future (Unless u have already done it) now would be a good time to install a variable cam gear.
Once its all been cleaned up, with all the oil & grease removed, bolt up the timing case first, so it presses up hard against the bottom of the head, and don’t be shy with the gasket sealer.
Then do the sump, drop the engine and walla.
You should be able to do it all for around $100.
On the other hand, I Can’t help ya too much with the rear main tho.
CAUTION: Slippery When BOOSTING!