Brent, the process works great; I've done it on several engines using an outboard motor pull-start cord (just stiff enough and a good diameter).
But...... it might be a bit "iffy" on the 103 engine due to fact that you will have to turn the engine backwards to lower the piston and get the cord out after the valve work is done. Turning the timing chain backwards against the chain tensioner is something some of the pros herein don't recommend. The tensioner and it's slipper are not the problem. But, the plastic guides get pretty brittle, and if the chain slacks just a bit coming off the lower sprocket backwards, it could possibly catch the end of the bottom guide. Could be a disaster waiting to happen. Probably wouldn't happen if you go slow and carefully, as the tensioner is strong and should hold the chain in place. but, if it did, you might not find out until the damaged guide jammed in the chain at 4000 RPM.
If you do decide to do it, have all the plugs out, the fan belt off, and of course the rocker arms will be off, and turn the crank very slowly and carefully when going backwards.
But to be safe I'd recommend the air method. Pressure adapters are under $5, borrow a compressor and do it that way.

Cheers,
DG

Oh, the exhaust and intake seals are slightly different - pay attention.