how would the valve locks fall? you press the valve hat - it exposes the locks - you use a magnetic pencil to remove the locks. to install the locks you use a small tool like a small forceps or small needle nose pliers to install back - you can use a dab of grease to stick the locks to the valve itself for easy install.
how would timing be a concern - timing is the crank relative to the cam rotation - your cam would be out meaning that all valves are positively closed (no issues with timing) you can now rotate the crank to raise and lower the pistons, whenever 0 mark aligns with the pulley notch, pistons 1 and 4 are at TDC whenever the notch mark is 180 degree across from the 0 mark on the engine pistons 2 and 3 are on TDC.
Once you have done all your valves - you rotate the crank to be a little before 0 mark - about 30 degrees - (so that no piston is at TDC) now install the lifters and camshaft and torque down the cam saddles - rotate the cam to TDC, now advance the crank to 0 mark and install the belt and tension correctly.
JOB DONE.