My best recommendation is to work with a qualified Titleist fitter to find the right shaft that helps you lower your ball fight and enables you to work your ball right to left.

The 915 stock shafts included Diamana M/S/D (red/blue/white). In order of descending ball flight. Buying a new shaft may be prohibitively expensive for a 4 year old driver. You can find a used 913-917 driver for a lot less money and use the shaft from that one in your 915, Or even a used shaft. Swapping shafts and reselling the pieces you don't use will be a low cost alternative. This does carry the risk that you may miss an optimal setup. Working with a Titleist Thursday for a TS driver can pay dividends for the next 3-5 years over a driver that is not the best fit today.

I keep reading how a "FITTING" will help almost everyone, what recommendation is there when the closest fitting is 800 miles away?

Hi Rory
If you're not ready to upgrade your 915 driver, and want to keep your expenditure down, then have a look at the Titleist Custom Options DRIVER & FAIRWAY SHAFT COMPARISON chart page 6 on the Titleist website.

media.titleist.com/.../Titleist_Custom_Options_UK_Sept18.pdf

You'll see a graph which shows you the various custom shafts and should identify some that suit the trajectory you desire, then have a look on eBay you should find one that suits your needs. Worked for me I upgraded the shaft in my 917 Driver and 3 wood by buying an ex Demo shafts at a reasonable price.
Hope this helps.

The Aldila Rogue silver was the low launch low spin upgraded shaft for the 915. It was an amazing shaft, I still game that combo as my backup set which I keep at my cottage.

I have the Fujikura Motore Speeder VC 7.2 tour spec X in my new TS3 driver and the 8.2 tour spec X in my 917 f3 3 wood.

These are both low launch and low-mid spin.

Check out www.titleist.co.uk/.../golf-shafts as you can select weight and launch options and see the available shafts.