Update on the rocker situation:

After extensive research and discussions with a few people on this forum, I came to the conclusion that the intake valves were borderline too heavy for the PSI 1512 springs that my Thitek heads came with. I replaced them with PSI 1513s, but I didn't stop there. I have replaced all of the rockers, intake and exhaust, with brand new sets; replaced all of the intake valves and machined the valve stems down to compensate for lash caps I added in the hopes that I can eliminate the rocker wear that seems to be fairly common with these engines.

I have to say I like the looks of the lash caps and how the rocker pads fit on them, the valve stems are 8mm, the lash caps are 11mm wide and the rocker pads are 10mm. So it seems to give a much more stable contact point. I also shimmed the rockers to make sure the pads were dead center on the lash caps.

Reassembled everything; I now have around 45 runs, and with each inspection everything has been looking good so far. At this point, I have to come to the conclusion that the valve springs being too light for the valves was the main culprit. However, the size of cam I am using may have just brought this to light a lot sooner.

I hope this information helps others in the future so they don't have to go through what I have been going through with this. Thanks to everyone who came up with suggestions.