I have a relatively new Jamis Renegade, 54cm, and I have the intention of mounting a riser stem to get the bars approximately level with the seat. I find the current setup with the stock stem flipped up to be very comfortable on the hoods for most of my riding, which includes both paved and dirt roads and twisty, only moderately technical (non-technical by NE standards) singletrack. I want the riser stem to make the drops a more comfortable position in the wind and when on technical downhills (allowing me to be in more aggressive position for longer periods of time, despite my bad back) and to make it so I take less weight on the hands when riding over bumpy terrain on the hoods.

I have a couple questions related to getting the right stem. When going to a riser stem, the horizontal reach to the hoods is going to be less for a similar length stem, so should I be looking at a slightly longer stem to keep the horizontal distance relatively consistent? For example, I could replace the 80mm 7-degree stock stem with a 90mm, 25-degree stem or a 80mm, 30-degree stem to get the height right. With the latter, I'd be giving-up 20mm of horizontal reach, but with the longer stem, I'd only be giving back 7mm of reach. I have plenty of room to slide back the saddle position either way, and I could probably stand to do so a little regardless, so I'm not currently thinking of going with a longer stem than 90mm. With respect to the angle of the stem, my general thought is that the lower the angle, the less stupid it looks, but otherwise, it's just a question of where your hands end-up.

My question is related to handling characteristics, as well as fit and feel. I don't mind making the steering arc shorter. Coming from a mtb and riding mtb trails on the CX bike, I generally appreciate the extra responsiveness. If I'm raising the bars, however, I'll have less weight on the front wheel, at least when on the hoods, and I expect that would be exacerbated by moving my position back. Where is this trade-off felt - in cornering stability, in enhanced OTB potential? I assume both of these will be compensated to some degree (fully?) when I am in the drops, but I'm trying to get a sense of how the feel of a bike has changed for those who have made similar changes as old age has required you to hybridize your road bikes before you were ready to give up riding like a kid.