You certainly don't need a cherry picker. Before simply assuming that the valves are the problem, consider another issue. We had a similar problem with a del sol dx motor. It sounded like valve train noise, so we adjusted the valves. It didn't stop, so we assumed the manuals were wrong, but they were right. Next we checked the compression on the pistons, yup... we blew a ring. The noise caused by a cylinder knocking, with can occur with a blown ring, can sound like valve noise.

Get a compression testor and see where your cylinders are at, that may be your problem, and that's easier to check than disassembling your head.

Jung