Some tips to save your sanity and religion
First off after the valve covers are removed plug the oil dain holes in the head with shop rags so no little parts can escape.
Second when removeing the oil rail pull up straight and level with a gental rocking motion. Inspect the o-rings for any damage. Set them aside on a clean surface and reinspect for trash before reinstalling. A good pactice is to change all o-ings anyway.
Caefully remove the electical connections without beaking anything. With time the plastic becomes very brittle.
The injectors need no special tool when you unscrew the mounting bolt it will jack the injector up out of the bore if it hangs a gentle tap with a small ball pean works. That and a gental rocking motion while comeing up.
Sometimes you need to losen the rockers a little for clearance. If you have to completely remove one, pay close attention to how it is assembled and do not loose the ball bearing.
If one is hard to pull inspect the bore for burrs o rough edges on the fuel ports. These will need to be removed with fine emery cloth before installing the new injectors, don't want to cut the new o-rings.
Be shure and get all of the copper washers out of the bottom of the injector bores and install all new washers. A long bladed screw driver that just fits in the washer center a gental tap just to gouge into the copper and a rocking motion will work the washer out of the bore if one is stuck down there.
Simularly take a large srew drive with a blade the size of the washer od twirl it around to clean any carbon build up and a shot of wd-40 to wash it out and good to go. Now there is a special tool for this but the screw driver works nearly as well and a lot cheaper as well.
At this point before reassembly I like to suck out any oil and fuel that may be sitting on top the pistons. A one man vacum brake bleed tool works good for this. I use a pice of 1/4 to 1/8 steel brake line about 18 in long with a slight kick bent about 3 in from the end and about a foot of hose to attach the line to the brake bleeder.
Insert the line untill it bottoms out on the piston, align the kick so it points towards the cylinder wall and suck out any liquid.
Hope this helps some.