Generally, an inch of headspace is recommended, but if it's still actively fermenting, you might want to leave a little more room.
I believe it's generally best to avoid overhandling your wine. Every time you rack, you expose your must-wine to oxygen. A little air exposure is ok, but too much can ruin it. You also run the risk of contamination.
The amount of sediment depends on how the yeast flocculates and settles. Some strains settle to form compact lees, others leave a lot of sediment. The amount of sediment is also influenced by the amount of solids or pulp in the must.
The amount of foam is also greatly influenced by the strain of yeast you are using. Temperature and various other factors also come into play. Don't worry about the foam unless it's spewing over like a volcano. If that ever does happen, moving the carboy to a cooler location will reduce the problem.
Reducing acid one year old wine 405Fishhead - Fining generally doesn't alter the acidity. There are some chemicals you can use (usually potbuttium or calcium carbonate are recommended) but they do...
At this point, the best thing you can do is to make sure the airlock is tight, then kick back and have a beverage. Worrying too much could lead you to do some things that would be detrimental to the wine-must that's in progress.
Greg G.
