When you load the ware into the kiln it is important that you maintain sufficient clearances between the individual pieces but also to the side of the kiln. Prior to the moment that it flows out the glaze may bubble to a sort of foam layer like shaving foam. This phenomenon and the manner in which it occurs may vary with the glaze that you use. However you should avoid that two pieces of ware „kisses“ each other in this stage leaving a mark on both pieces, or that the insulation blanket is touched. Keep in mind that, how easy it may look when you load the kiln with your bare hands when everything is cold, things may become much more complicated when you have to unload with a pair of tongs and with the ware at a 1000 ° C. You should have sufficient space to move with the tongs in the kiln in order to get a good grip. Make sure that the bottom of the ware is free of glaze. Glaze marks on your kiln shelf are not or very difficult to remove. If you use a triangle to put your ware on you must be very accurate with picking it up with your raku tongs. To put ware back on a triangle because you feel not certain in this stage can get very complicated. May be a bit of practice how to pick the pieces of work when they are still cold is not a bad idea.
Larger pieces of ware should preferably be positioned at the side of the burner port in the kiln. Here they will affect the draft through the kiln less than placed on the opposite side.
There is also second reason for this. With the kiln being heated at the bottom, the temperature will vary with the height of the kiln. The higher you are in the kiln the lower the temperature is. In terms of glaze being ready or not the highest piece is crucial. If this piece is ready, than everything else that is lower will also be ready (assuming the same glaze recipe). When you place the highest piece at the side of the burner port you will see that you automatically are at the opposite side (safety) to check this through the flue gas port in the cover of the kiln.