Reed and sedge peat are formed from rushes, grasses, sedges, and similar plants in marshes & shallow lakes. Reed/sedge peat (also referred to as Michigan peat, as Vance noted) are too fine of texture, and decompose too rapidly to be of use in bonsai soils. The product is widely available here in The States. Answers to your questions: Reed/sedge peat are used as a soil amendment in gardens and beds and are poor choices in container soils of any type. They are less acidic than sphagnum peats, too. Peat muck (bonsai) is a mix of ingredients that is used to build walls or dams that hold bonsai soils in place on slab or tray plantings. They can also be used as soil on rock plantings. It is often a mix of sphagnum peat and some form of clay or bentonite, but there are many recipes for peat muck. Reed/sedge peat could be used in a muck mix, but it is probably better to limit it's use to use in material for soil dams & to use sphagnum peat in soils that occasionally call for peat (rock plantings e.g.). Al

Spoke with a family member who's an engineer with lots of "sperience" with concrete. Here's what he said. Concrete is something that of which I know. More water does mean less strength, but poor workability leads to incomplete consolidation, air pockets, sand pockets, and other stuff that is worse than the slight loss of strength caused by a little extra water. The peat moss is a special case. Since peat has no inherent strength, it needs to be saturated with the cement paste. If the peat particles are already saturated with water before the cement is added, you'll get less cement saturation of the peat. So, don't add the water to the peat and then throw in the cement. Better to make a cement mix a little too wet and then throw in the dry or slightly damp peat. The peat will suck up some cement paste. This is a good thing. Even though it stiffens the mix somewhat, you can readjust the workability with a little more water or a little more dry cement if you get too heavy handed with the water.

oldmonk, check out the link below for information on Sphagnum moss suppliers for a start. Canadian and Chinese S/Moss is shipped all over the world. "Horton" Here is a link that might be useful: Sphagnum Moss Suppliers

To come back to soil/soilless for a moment (was working all day), I think a lot also depends on how many plants you have, where you grow them (inside house, outside, greenhouse), and your climate. My cacti, around fifty, are outside during the summer, and I don’t have anything to protect them against rain, except for moving them inside temporarily. In their soilless mix, they can take unexpected showers, even if the temperature drops more than I like for them. In a greenhouse, where I could control water, I might experiment with adding soil to my mix and seeing what worked better. But without a greenhouse, gritty works best for me, just about eliminating plants dying from overwatering. I don’t have so many plants that watering a bit more is a real problem. Of course it helps that our summers are comparatively cool, however much we complain about the heat ;-). Most of my haws and mesembs stay inside, and because they aren’t exposed to the direct sun and heat, on the whole they do fine in LP and pumice respectively, with me watering every 5 to 7 days. Another factor is the experience of the grower and a knowledge of individual plants. All in all, it is useful to have a number of choices laid out, if possible with reasons and circumstances, but in the end, everyone has to chose a starting point and then learn from experience.