valve tappet adjustment is expensive business on this engine as shims are required to be replaced on the lifters to achieve correct thickness, In toyota books there is a tool required to press the lifter and pull out the shim with a set of thin pliers (DO NOT USE A MAGNET EVER), using a magnet will magnetise the metal and it will attract metallic particles and wear out the lifter bores.
anyway - now I'll tell you how I did it. I measure all valve clearances and write them down, then I write what needs to be achieved, Now I remove the camshaft, some shims are swapped around for correct clearances and some need to be bought from Toyota.
While at it and if the engine was using some engine oil I change the valve seals, I pull out the lifters with a suction cup and use my valve depresser tool and mount it on the head and remove the valve springs of cyl1 and cyl4 - with engine on TDC both pistons for 1 and 4 are on top and the valves rest on the face of the pistons so they cannot fall into the cylinder. I put in new valve seals with the help of a falooda straw (to prevent the valve collet grooves tearing the seals) and a dab of sealant on their base edge.
They will slide over the straw, passing the collet grooves and snap into the valve guide, install springs, covers and collets. Both 1 and 4 done, rotate the the crank 180 degrees to do cyl 2 and 3 the same way.
Valve seal job and valve clearance job done.