Have you tired using the “snap feature” before you final cure the part?
I have been using clear and grey for mechanical functions since I got my Form 1+ I have found the clear to be pretty tough if you can engineer it to take the forces properly. For me I have the clearance to increase thicknesses to support the impact that my parts see but even then I usually have a 30% risk of fractures. With out knowing the design of the part I would try to use the snap feature before your final cure because once it is fully cured it is extremely brittle. the flex material is okay but if you have fine geometry you will not be happy with the print results. I have never used any other resins in the form 1+ yet but usually you need to be sure of the settings I know a lot of guys use a different brand of resin here but they run with certain settings for the LASER exposure.