i've got a old Schumacher turnbuckle on the elevator run, it's 3mm metric thread, one end its right handed thread, other left, so you can turn the turnbuckle whilst in place and it adjusts the distance, even ore acurate than the half turn you have on the clevis. works perfect, just need to find more at the right lenght now for the rest... or... Carters? how about going into biz with me.. also got a servo based idea that the factory you work for "might" be able to produce