If I had had the extra filter in the old tank for a few days, would set a day to move the old gravel (with it's bacteria colony to the new tank without drying it. I would also move that 60% of the water (though the vast percentage of the good guy bacteria is on the gravel, tanks sides, filter, gravel and any ornaments, not in the water). If the temperature is above 76 degrees F/ 25 C. the next day, I would be comfortable moving in a half dozen guppies in the next day. You have already given your nitrogen cycle a good jump-start. ;)

The following week you could add a couple of scavengers, though a gravel vacuum is more effective at cleaning the bottom. Bottom fish are just fun to have though. Corys are popular with guppies. Most loaches are ok, though Scott L has suggested that one avoid skunk loaches, which can be surprisingly  unpleasant. Others have had weather loaches in with guppies, though I have this mental (?) image of weather loaches going into their "its a storm front" hyper-activity and potentially knocking the guppies around. Generally the guppies are smart enough to get out of the way. ;)

Check the quicklinks for guppy plants. They will add color to the tank, add a little to the ecosystem and the guppies will many times show better among them. Floating plants (there are a couple great nominees) will assure you a supply of fry.

29s are fairly deep tanks, a lot of the light (50% ?) emitted at the top of the tank will not reach the bottom. For other than the really low light plants, you will need 2 watts per gallon of light.

As for guppies, I would get the nicest ones you can reasonably afford. You are probably familiar with fish shopping. Others may again want to consult the Quicklinks for suggestions in avoiding the purchase of sick fish.

Try those tricks for speeding up the establishment of the new tank. Please let us know how things work out for you.