A few people have tried 26 degrees advanced and seemed happy.
I have not heard 28 degrees batted about much but might be better for vegatable oil burners. The flame front is slower with the vegatable oil perhaps.

Jkoebel.
In only my opinion the faster you start to work on your own car the better. These older cars almost require it to some extent to keep your wallet somewhat intact. Plus the experience builds self confidence.
This site makes it possible for even newcomers in my opinion and is one of the attractions of this car. Some of the garage bills today have no mercy component at all in my opinion. In fact I almost find them unbelievable.
You can easily equip yourself with the required tools with the savings incured by doing it yourself. Most jobs are pretty straightforward as well. Have you even established you need a new timing chain? Someone else could have already changed it not that long ago in milage. At least check out if it is really needed. Any money saved will find another home. It always does..