I use dowel and glue to attach the heads . it is time consuming to get a good fit to the handle and I do drill the hole out both into handle and the head before I start carving. then I have re-drill the hole for the threaded bar out to ensure it slides fully into the handle,
If the heads going to be painted its easy cover and slight errors on the joint with filler and paint .
I will carve the head 1st roughly carves the handle but leave the area around the joint where the head and handle meet carving this when I fix the two pieces together then finally carve it . I will just leave enough room to insert a buffalo horn collar .but this is filed and polished to ensure a good fit onto the shank/
When the handle collar is fitted to the shank I finish of the handle working around the horses head .
Its a slow job but unlike the horse its not a race
other toppers I have done in a similar fashion