Mornin' DW, I use that method when making standard lamps. Easy enough really, just make sure the mortise and tenon are a reasonable fit, not too tight. I use a open end spanner that fits a drill bit, this way you don't have to measure, the mortise or the tenon when turning. Also try and turn a feature where the join is, say between two beads or something like that, then you can't see the join.
Also this joint is slightly weaker than the rest of the piece so treat it accordingly.
Bit of advice drill the hole before you turn the spindle, then tail stock in the hole will centre the spindle up for you.