Tru-Turn products are great, but their adapters only fit the SHCS's that their (and probably Dave Brown's) spinners use. I don't recall if that's 8-32 or 10-24. The Brodak and Randy Aero spinners don't use a SHCS in the nose (and look a lot slicker as a result), with 1/4-28 threads machined into the tip piece. I have had some problems with the tip threads being too short, and got it done with a coupler nut from Ace Hardware.
I'm really not a big fan of aluminum prop nuts...lots would be made from 6061-T6, which I don't think is wonderful enough for long term durability. Pull the threads out at a contest and you're screwed, unless you want to carry spares. Steel is more reliable for this task, but 7075-T6 would be a lot better than 6061. Depends on how critical weight is, and whether your plane is tailheavy or noseheavy, of course. If it's already noseheavy, a touch more tail weight won't be a huge deal to most of us.

Steve