I've always had thin-wall liners installed, K-Line is/was a popular supplier, they sell a complete kit, tools and all. The idea is to line the guides with manganese-bronze (or silicon-bronze in the old days) to prevent damage to the stainless or Ti valve stems. Of course I'm old, and although K-Line is still around, there are other players on the field today as well.
In terms of the thick-wall guides, some old familiar names sell them, like Sealed Power. Ferrea valves sells them, I'm not sure about Manley. I'll bet Rev Valves sells them too. Some of them have one end turned down for the spring loaded seals, but I don't remember which. Your machinist will probably have a preferred brand, if you're using a machinist.