Interesting. Do you need them to be shortened or was it just what they were when you purchased them? Being that they are 917's which is a slightly older model, you can probably get the stock shafts on eBay for a decent value used. That may be a better option if you prefer the stock length.

You would need something like 10-12g of extra weight in the head to restore the swingweight lost by cutting down a driver from 45" to 43". Removing 2" from the length of a driver lowers the swingweight by 5-6 points and it takes roughly 2g of weight to increase driver swingweight by one point.

But the Crossline Midsize grip is also about 10g heavier than a standard grip which will reduce the swingweight by another two points or so. That would take yet another 4g of head weight.

I do not think you would like the overall weight, balance or feel of that driver if you added 15g of weight to the head. And in any case I do not think there are 12g+15g=27g weights available. Start with something smaller, adding perhaps 8g or so of weight to the head and see if you like it better.

If you can find a 25g grip (such as Dri Tac Lite), that would help. There are Winn Dri Tac Lite midsize available on eBay. According to several sources, Lamkin Crossline midsize is 62g and that is a loss of 2 swingweight points vs standard. (52g). 38g difference is slightly under 8 swingweight points between Lamkin Crossline midsize and Winn Dri Tac Lite.

Correction on the swingweight loss: it is 3 points per 1/2" so the loss from 45 to 43 is 12 points. I have a 913F driver with 44" Bassara 50g shaft, Excel RF oversize and 15g headweight and it comes out to D1. The heaviest weight you can get for a 917 off eBay is 16g. That's only two swingweight points. The length of the 5 wood stock is 42.5 so that would be a loss of 9 points to 41"

There are plenty of shafts that fit 917 driver and fairways and they are about $60 each on eBay.

If you are comfortable with 43" driver, the best you are going to do in swingweight point increase with headweight of 16g and Dri Tac Lite grip is 10 points vs a stock headweight and a Lamkin Crossline midsize grip.

I had the same situation with a TM Burner 2007 driver up until 2017. The stock shaft is 45.75 and my normal driver shaft has been 44.5. I had to use a Dri Tac Lite grip to even get it close to D0.