In your case it might be worth it to consult with a local shop, to at least get things checked and measured properly.
I’d suggest the same thing.
I just recently had some heads dropped off to look over, since the cars performance was less that expected.
These are aftermarket heads.
Someone ordered a roller cam and the parts that went with it.
They put the springs on the heads....... but the springs were listed for use on stock heads and stock installed heights...... but the aftermarket heads have quite a bit taller installed height.
None of this was checked, and the new springs were just installed on the new heads.
The result was...... the springs were set up with the seat pressures over 60lbs lower than they were supposed to be...... so now the valvetrain is floating the valves...... and the car is slow.
I see this stuff
all the time.
The valvetrain is one of the places most often set up improperly, with the end result often requiring a bunch of additional money being spent to correct it.
Since the OP has admitted he doesn’t understand it, buy a book that gets into the details about prepping and assembling performance cylinder heads....... and don’t put your own heads together until you read and comprehend the info from the book.
Or pay someone with the experience and equipment to do it for you.