I made a couple of “adjustments” to my HF compressor that helped get more compression. I bent these tabs perpendicular so I could grab onto the lowest coil. Next, to keep the damn thing from slipping off a coil I used a small chainsaw sharpening file and created a groove for the jaw to latch on...
Get a soft drink straw, cut like one inch pieces, slip a piece over the valve stem keeper grooves, slide your new seal over the straw to prevent nicking the new seal.
Are you using the clothes line method, or compressed air? If you’re using the HF spring compressor pictured, I feel your pain. I even modified this one and it still was a pain in the ass to use. One tip I’ll give you, is when your doing one next to a valve cover stud do yourself a favor and jam...