MID/END MARCH
The seedlings should now be well esablished with at least 4 leaves. An algae may have formed on the surface of the compost and this should be "scratched" with a nail to re-establish good drainage. Be careful, of course, not to damage any shallow roots.
When the plants are strong enough, they can be transplanted into individual 2" pots.
Fill each pot to within 1/2inch of the top with good potting compost, wet and leave for 10 minutes to drain.
Now comes the time to decide how many of which to grow on and bear in mind that a few "spares" is a good idea.
Gently tease apart the seedlings and transplant into the individual pots. Again, remember to label each variety, water in and place back into the propogator. The temperature should be turned down to 25°C, 77°F. An excessively hot night temperature will tend to draw the plants and make them spindly.
It is a good idea to take the propogator lid off every day and give the plants a "waft" of air to help prevent any fungal diseases which could start in humid conditions with no air flow.
Keep watering as necessary, but don't waterlog them.

END APRIL/EARLY MAY
Choose 8, 9 or even 10 inch pots, wash and sterilize as before and fill with potting compost. The seedlings should now be quite strong and the stem should be "woody".
Transplant the seedlings into the big pots, label, water and place them onto the staging.
Retain a few spares, but don't transplant them. Discard or give away any surplus plants. Wash and sterilize the propogator and store for next year.
Now, the main grenhouse heater can be switched on to keep the temperature close to that in Mexico or Thailand. There could be a cost v effectiveness arguement here. Some say that the temperature should be a minimum 25°C, 77°F, but this will create a large electric bill.
Setting the thermostat to 21°C, 70°F is a good, effective compromise. There will still be a bill hike, but this is the cost of the hobby!!!