Thank you to everyone that responded with expert suggestions and opinions. After much thought over the last 24 hours, I've decided to move forward with the following plan of action:
1. Fire my mechanic who said I could simply downshift to do the same as the KD linkage
2. Order the Lokar kit (already did via Jegs)
3. Going to visit the local trans shop to inquire about a full rebuild of the A-904
4. Hope that the trans shop is knowledgeable enough to help me hook up the new Lokar kit correctly
5. Consider changing the shifter out - I don't like the aftermarket one my Pop installed. I'll seek the guidance of the trans shop on this one......