I just received this one in the mail yesterday to change springs and seals on my TBI L05 wagon. I'll report back later today how it does.
Years ago I bought a simple tool that's used with an old rocker arm shaft that worked well on the Buick. I thought it came from Kirban's but I don't see it listed there now.
I just did mine this spring. I tried 3 different valve spring compression tools. Don't waste your time or your money on any of the tools out there. This is the only one I could find that works with the heads on the car. It was actually very easy with this tool. Even number six cylinder was all breeze. I have AC and heat.if you are interested I will sell it to you for $50 shipped. That is a little less than what I paid. It has only been used one time.comes with instructions and Tips.
As a follow-up to my post, I just got done with one of my Bowtie heads using the eBay tool. It worked well on that application and I imagine it'd do OK on the Buick. Given a choice though, take up Bill's offer.