The fertilizer and crystals don't matter - you won't need to fertilize the sprouts and the crystals keep your seedlings moist longer, so you have to water them less. Most people on this forum recommend ProMix (myself included). That seems to be the best for inclusions (stones, sticks, etc.) but is a bit more expensive. I had difficulties finding it at Walmart, Canadian Tire, or Home Depot last year. Just be sure what you use is soil-less, sterile, seed-starting medium and not a soil.

Personally, I do not use anything by MG. I was at our Walmart yesterday and got Schultz seed-starting medium Plus (a time-released fertilizer included) 14L bag for $5.35 CAD. I have used Shultz before - not the best - but saved me driving to the next town to get Pro Mix. I will probably go out for a bag when it warms up - it's rather icy here now. Hope this helps.

This year I have used both Pro-Mix and MG Seed Starting Mix and can't see much difference between them. I sometimes add extra perlite and course sand just for the heck of it. Don't know if it makes any difference to the seedlings.