If your laptop is a pretty decent one (IE: something over a pentium 1) then you probably shouldn't get any noticeable delay to begin with.
Maybe you would have to tweak the code and recompile SynthFont, but in the binaries, the minimum output buffer is 0.5 seconds. But all the sounds pass through that buffer, so every notes will be synchronised.
It only matters if you use an input device such as a keyboard: there will be a (constant) delay between the moment you press the key and the moment you hear the sound. I shouldn't be a problem since many people compose by putting the notes on a notation software. I doubt you will use a MIDI keyboard with a laptop!
If your computer isn't powerful enough (cpu, ram, IO), the sound will kind of stutter and the midi playback may desync... had some weird effects with yamaha XG on a 486/33, where all the "notes" (midi messages) of a bar where played on the last beat.