Ha Ha! Fun stuff huh?
I know where your coming from man.
How many miles are on the engine? After a lot of miles, those tiny oil passages in the rockers just get gunked up and you have to completely disassemble the valvetrain and clean it all real good. I guess you put in new HLA's right? The old used ones will get worn tips when they've been oil starved for a long time.
I have low miles on my 1991 B2600i 2WD truck but the previous owner must have overheated it or tried to adjust the timing chain and screwed up the head........they purchased a new head, put it on, didn't have the timing chain set up right, but fired it up anyway and bent all 4 exhaust valves........then got pissed and hauled it in for scrap metal...... I found it at the scrapyard before anyone got their hands on it, and bought it. Replaced the exhaust valves, got the timing chain on right, and checked it (by turning it over by hand first!!!), got it running good and it's my daily driver now!
The first thing I would do is try the Mobil 1 oil filter and new 10w30 conventional oil. See if that helps any.
I was having trouble with my HLA's after the truck sat for a day.......seems the oil would drain out of a couple lash adjusters and it would clack like heck for the first 10-15 miles or so, then quiet down.......until the next day! The Mobil 1 oil filter cured that! It no longer will clack after sitting, unless it is a week or two that it sits, but it also goes away a lot quicker than it did also.
The oil filter is twice the cost of the normal Fram or Purolator filters, but I'll never put a regular one on it again! It works THAT good on my truck! Also, I won't use Fram on any of my vehicles!
Does the oil light flicker on any more, or was it because the pickup tube screen was blocked with timing chain guide material/debris?
Here is a pic of the Mobil 1 oil filter I am using.....
I think this anti-drain back valve in the filter is the reason it helps keep the oil in the valvetrain overnight....actually, over the week!