Brice, Some time in the last year or so I measured the two Hercules, the two sizes of Osprey, and several other Hunter tools - basically everything I had with angled cutters. I'm sure I did this while communicating with Mike about something but unfortunately I cannot find the email - maybe we discussed them by phone. If I can't find the paper where I wrote them down I could measure them again, probably Sunday afternoon or evening. (unless someone beats me to it) I think I have the #3 Swan neck (that's the one with the 10mm cutter, non-tapered shaft?) but I'll have to check. I get so confused with his number/name "system"!
Do you want to know the angle on the large Osprey or the small one? (in case they are different) I think one has a 6mm cutter and one an 8mm cutter. I don't know what an Osprey HT is.
I've used both the tilted and non tilted cutters. The tilted cutter like on the Hercules and Osprey really excel when using the tool as a gouge in the bevel-rubbing mode, cutting spindles, the inside of a bowl, etc. You have very good support from the bevel just like a spindle or bowl gouge and can take deep or whisper cuts. I don't think I've every caught one. Both tilted and non-tilted cutters work fine when used as scrapers tilted sideways (rotated a bit counterclockwise), say inside a steeper-sided form such as a box. I don't think there is as much difference between when used like this.
BTW, I shape the heel of the bevels and polish them like this so they don't burnish the wood when cutting in the bevel-rubbing mode:
hunter_hercules_mod.jpg
Here are some of the angled cutters, two Hercules, small Osprey, the Clewes mate - I guess you could measure the angles from the photo. Some in this picture are not yet modified:
HUNTER4_side_IMG_20160803_1.jpg HUNTER4_top_IMG_20160803_10.jpg
JKJ