For sure it will make the shaft play stiffer. Depending on the manufacturer, two flexes stiffer. The spin rate will probably decrease but it will depend primarily on your swing.

From the Fujikura website: "In general, tip trimming can be used to achieve a stiffer shaft profile, lower launch, and/or lower spin. Tip trimming 1“ is equivalent to one flex. For example, if you wanted to stiffen your S flex to an X flex then you would tip trim 1”. If you prefer to play shaft in between S and X flex, you would tip trim 1/2”."

I looked into this and spoke with my authorized Fujikura custom builder prior to having my Fujikura Ventus Blue 6x playing @ 44.75" tipped a .5" My swing speed is 116-117mph on Trackman and we decided we could tip it a but but not quite the full inch, which would have been the recommendation had I been around 120mph SS.

Tipping can change everything. I had a Ventus Blue and tipped it 1/2" thinking it would just stiffen it up a bit, and my first outing I was convinced it was a mistake. Should have taken it out to the driving range to get a feel for it first. After working with it I get a little more control and a bit lower trajectory. Very happy with the result.