Peter:
I'll relate what information I've been able to gather.
Howards first bowyer was
Dale Phillips 1949-1954
The woven glass bows were made in 1952-53. I suppose it possible that some glass was left over and made by other bowyers, but the number of bows would be small.
Jim Darling 1954-63
Stotler was in that same time frame, but I have no firm dates. Jim primarly made recurves and Stotler the longbows.
Some where in the late 50's thru the mid 60's Dan & John Schultz were the bowyers.
1965 Howard moved back to Alabama and in 1968 Ted & Betty moved to Hamilton,MT John Schultz was their bowyer thru the mid 70's, Then John went out on his own.
Tim Meigs built bows for them out of his own shop in Carson City, NV. from 1977-1995
Ted Kramer also made bows for them from his shop in St Ignatus, Mt during that same time, but I believe only until the 1980's
Craig Ekin started building them in the late 90's up to present time.
Howard Hill Productions incorporated in 1960 as Howard Hill Archery and moved to Sun Valley,Ca.
Some time in the late 1970's Howard Hill archey recieved a copyright on their name. I don't think Stotler Archery ever used the Hill name. Ben Pearson sold Products with Howards endorsement but not sure of the exact time frame.
Shawnee Archery sold product for Howard from 1958 thru 1960-63 Then Ted and Betty sold their half of Shawnee Archery to Brother-in-law Dick Garver and started doing business only as Howard Hill Archery, moving to Hamilton,Mt as indicated above.
Hope this helps.
Bob