Oil seals; from a car dealer, Yeomans, (heavy on Toyota) in Brighton, UK.
(the spare part manager there has sorted me out several times with spare parts that Toyota Thailand is not able to deliver)
Well if you say 15 minutes/valve ain't too bad maybe I shouldn't complain, but my expectation would be kind of 2 minutes/valve.
I got pretty frustrated with clamping on the plier then playing with knitting pins and mini screw drivers to get the keepers in place, and stay in place when the plier was released.
Putting keepers in place in the retainer before compressing the spring never worked, the fell off during compression.
Tried oil/vaseline/grease in order to get the keepers to stick, did not work, didn't try glue though.