Newbie here looking for some help - I have a 1996 GTX (787) that is leaking fresh oil into the hull.

We bought two identical GTX's last year; re-did all the fuel lines, rave valves, plugs, wear ring, & pump oil.
First ski I noticed a build-up of oil in the hull while running at the house and was aware of a potential grommet leak from the bottom of the tank; placed a shop rag under the tank for the initial lake test - did not see any oil on the rag but did have a noticeable amount in the hull; the ski also fell flat approaching 40mph and appeared to go into limp mode - I'm assuming (hoping) it's the rectifier as far as that goes.

The second ski tested just fine; ended up parking the first one as it was a bonus.

- I just pulled the oil tank. Top grommet with the oil sensor was noticeably loose and came out when just removing the tank; bottom seal is maybe a little loose but then again I don't know what's normal.
- The two lines on the bottom of the tank looked relatively good.
- The single line going to the top of the tank appears a little more worn (3/8-1/2 clear tube); I assume this is a return line, routes to the port side under the exhaust manifold.

- Return line possible culprit? Either cracked tube or loose clamp?
- Appears I need to remove the exhaust manifold to access - Yes? Procedure?
- What else could be the problem? Any oil pump or seal I should check?

Thanks in advance and sorry for the Newbie questions...

EDIT: I just picked up some 3/32id Tygon lines to replace the factory original injector lines.

How best to access the return oil line? Remove the exhaust manifold? Does it require lifting the motor at all?
Any suggestions or links for changing oil lines or bleeding system once done is appreciated.