Glad to see he's still going so well, mine are in between the first flush of flowers and have new ones on the way. From my experience they seem to put their all into flowering and fruiting so I think this is why this seems to be their "delicate" time. I have found that just making sure they are watered correctly and having ready access to food ( these plants are so greedy, as you've no doubt noticed) should be enough. Have you picked up on the honey fragrance of the plant yet? If the air is still I can often smell it when I walk into the garden, let alone get close to the plants.
I didn't get around to sowing more this year, I have seed from my own and a different source sitting at home, tempted to do a late sowing but with the very dry weather and limited water around I may wait till next year now. When I've germinated them ( including your one) I just sowed them direct into their pots with nothing else done to them. They didn't all germinate immediately, some were a couple of weeks behind the others but there was more than 90% in the end.