Thing is compression & leak down really won't tell you much, the oil getting in the cylinder will seat a ring issue, valve guides don't effect cranking compression... What a compression test will show you is a burned valve, a head gasket... Not an oil consumption issue...
Alan mentioned valve seals & thats a possibility but honestly the guides would have to be toasted to use a qt of oil every 100 miles... If you do decide to dig into the valve seals don't work about the exhaust seals, they are under pressure, lots of engines don't even run exhaust valve seals...The intake seals are under vacuum & try to draw oil into the combustion chamber.. But thats also why an intake gasket will draw so much oil, it's under vacuum... And I've seen a intake gasket cause minimal drivability issues while burning a qt of oil in 20 miles... Why? Cause the oil seals the intake leak & you don't induce enough air to effect how the engine runs.....