Torque wrench = $75, and can be used on other mods, sold etc.
Results of improperly tightened strut bolts:
Under tighten: ? dunno what this could do- strut tower would wiggle & fall out? Stress body metal due to flexing? Would also defeat point of STB.
Overtighten: Strip bolts, have to have bolts removed at shop (after getting car towed to shop) at least $150/bolt, plus replacement parts & re-install.
I'd go with the torque wrench. I don't think anyone can tell 35 ft/lbs by hand.