Hello Mr. Blunt..

The tip is probably being burned because of the nutrients found in MG soil...

It will probably not be a big deal.. DO NOT add NUTRIENTS! NOT yet at least...

Keep the soil moist for the first 7-10 days... Seedlings have fragile roots...

Since you are using CFLs, you can flower when yo have 4-5 nodes.. and I reccomend it!

cheers
and thanx for the pics!