You can eyeball IP timing. Set the engine to TDC. If you can check for #1 TDC by checking cam lobe position through the oil filler hole, so much the better. There's a pointer at about the 11 o'clock position of the crank damper. The damper has graduations around a O|T mark. Numbers to the driver side are BTDC, numbers to the passenger side are ATDC. Remove the plug that takes a 17mm socket on the side of the IP. Same place you attach the IP locking tool and the A-B timing light. Use a mirror to peer into the hole in the side of the IP as you slowly turn the engine CW (the normal direction it turns). Look for something like the end of a flatblade screwdriver to center horizontally in the hole. With the lug centered, read crank timing off the crank damper. Ideally the lug will be centered around 15* ATDC but if the engine wasn't at #1 TDC then it'll have to go a full rotation back to TDC and then to about 15* ATDC. Do this 5 or 6 times then average the readings. Spec is... uhh... 14* or 15* ATDC. My memory's slipping so I don't know if 14* is where I like to set it or the actual spec.

Seems like you know how to adjust timing so you can check if you have the range to hit 14-15*. If not, the engine vacuum pump has to come off so you can reset the IP timer sprocket. This isn't necessary but it'll be useful to set the IP at the middle of its adjustment range. The bolt at the center of the IP timer has left hand threads - CW to remove, CCW to tighten. There's an arrow on the bolt to remind you of this. Set the shank of a big screwdriver through a hole in the cam sprocket to hold the chain as you loosen the IP timer bolt. Remove also the chain tensioner then gently turn the cam CW to move the slack from the passenger side of the cam sprocket to the driver side where the IP is. Stop turning the cam sprocket if there is any tension or resistance whatsoever. With chain slack over the IP timer, slip a stiff card or thin metal sheet between the chain and cogs of the IP timer so the timer is free of the chain. Remove the IP timer bolt (don't worry about the chain), pull out the IP timer without turning it then replace it one spline in the appropriate direction to get the IP within adjustment range. Engage the chain in the IP timer, install the tensioner (I think it's safe to skip bleeding for now) and give the engine a couple of turns to see if the IP is within adjustment range. Repeat as necessary to get things as close as you can with your eyes (which is probably good enough) or do the math after counting IP shaft splines. Don't forget to prime the chain tensioner before starting the engine.

Sixto
87 300D