Crack the line, don't disconnect it completely. A half turn is usually enough for fuel to dribble out of the fitting. Nothing you can't quickly wipe clean. If fuel doesn't leak out with a full turn, the line is probably dry.

There are many ways to check IP timing in a 60x. All involve checking crank position when the timing lug visible/accessible through a port on the driver side of the IP is centered in the port. You can do this as simply as looking in the port, a mirror helps, and turning the crank CW until the lug is centered to the best of your visual acuity(sp?). A little more precise is to use an IP locking tool. The lug is centered when the locking tool engages. Read IP timing off the crank. More sophisticated is to use an A-B timing tool or light. A sensor fits into the port to detect the position of the lug. You watch a couple of LEDs. When the lug is close, one LED will illuminate. When the lug is centered, both LEDs will illuminate. As the lug moves away, the first LED will go off then the second LED will go off. This tool costs $3-400. Maybe more now. The most sophisticated method is a tool which consists of a sensor and a timing light. You use it as you would a gasser timing light. You should be able to rent an IP locking tool and an A-B light in the tool forum. You don't need both.

The timing access port is covered by a bolt that takes a 17mm wrench. You'll do no damage by removing the bolt and turning the crank (CW only!). You'll lose a teaspoon of engine oil.

Pulling the crossover pipe is inconclusive because oil could be coming from the turbo or the valve cover. Remove the hose from the valve cover where it connects to the turbo air inlet hose. Cap the fitting in the air inlet hose and direct the valve cover hose into a vented or unsealed collection bottle. Drive around for a while to see how much oil collects in the bottle. You can clean and/or dry the crossover pipe as well as you can. Any oil in the crossover pipe will come from the turbo... assuming there isn't a pool of blowby oil sitting in the turbo.

Sixto
87 300D