Have you seen the various graduated reduction schedules? They can give a 1mg reduction in 7-8wks reducing by .5mg at a time, but with a softer more gradual taper. For example, this is my reduction schedule. An 8mg reduction would go:
WEEK 1: 8mg / 7.5mg / 8mg / 8mg / 7.5mg / 8mg / 8mg
WEEK 2: 7.5 / 8 / 7.5 / 8 / 7.5 / 8 / 7.5
WEEK 3: 7.5 / 8 / 7.5 / 7.5 / 8 / 7.5 / 7.5
WEEK 4: Stay on 7.5mg to stabilise and monitor for pain

Others have shared their variations on graduated reductions. Some go straight to alternating days of the existing dose with the new dose to give a .5mg (or 1mg) reduction over a couple of weeks or more.

Do you record your daily morning pain levels on a 1-10 scale to keep an eye on changes as you reduce? It was a suggestion I found here at Mayo that has been very useful. For now, staying on 8mg to stabilise for a while as suggested by your rheumatologist sounds sensible. I do hope you find a graduated reduction schedule that works for you. Keeping inflammation under control consistently without flares seems to be key in getting over PMR.