Is it better to use the magnetic probe or should I just use the timing light?

which direction on the timing tab is advance and which side is retard?

 

timing light will not work without the injector pulse sensor.

 

Here's a good thread with instructions on setting the IP timing on your IDI. Don't forget that rotating the IP toward the passenger's fender advances your timing, and toward the driver's fender retards the timing.

https://www.oilburners.net/threads/h...uipment.91235/

Here's a website which has a .pdf download of the DTI 3300 instructions

https://tinytach.com/timing-equipment

I have the SnapOn MT257B so I'm not familiar with your timing tool.