RallyBob is right, I forgot about the grit and cleaning. Scartch that one, it's a bad idea.
The idea of doing this in the car is definitely not ideal. But it can be done. A creative person can get by without a hoist, but they have to be very careful about safety.
While it may seem easier to just pull the motor and rebuild/replace it, the money, time, or resources to do that may not be there. Or may not be the goal. Jimsky's original idea of using the 1.5 head to increase power was a 'stop gap' measure until he was ready to rebuild. My opinion is that the work needed to redo the 1.5 would take more effort and money than swapping in a set of used flat tops. I've had my GT engine layed open like this. Not for this reason, but I had the head and oilpan off and the engine support out of the car. It was much easier than pulling all of it out of the car. In the time it would take just to get the motor ready to drop, I was already working inside the engine.
My question in all of this, since I didn't think of it before, is this- would the modified 1.5 head be useable on a 2.0 or 2.2? Or would the effort be better spent to do a 1.9 head the same way if a 2.0/2.2 might be the final set up?
It really depends on what the theoretical final goal is. A nice rebuilt stock (more or less) 1.9 with about 100hp? Or a search for 125hp+ for extra fun factor?