I have done two 3.55 conversions with a knowledgeable friend (who had never worked on a torque-tube).
I had never been inside the torque rear-end at that time & I had never done anything in any differential.
My experienced/professional friend had done R&P changes in modern rear-ends (he had never seen the insides of a torque-tube rear end).

We had the complete installation kit.
We had all necessary tools (in a vehicle demolition/recycling-yard garage) and gauges (from Harbor Freight) and Prussian Blue (from NAPA).
We custom-made a few pipes that served to remove some seals/bearings/gears (as I recall).
We studied Patricks installation-procedure sheets several times (it was barely legible).
We did not have the benefit of Sweet's excellent Tech Tip.

The first time took us two long nights (which included cleaning all parts inside and out).
The second time took one long night - the outside of all parts had been cleaned in advance, and we knew what we were doing.

I am 100% pleased with the results.

I would not have tried doing this by myself, either time (or, in the future).