Larry
The altitude is of little value off the gps unless you decide to add or subtract the barometric difference, therefore I rely solely on the barometric altimeter.
As to the indicator I use the HSI function screen with the ground speed and distance to wp showing. The new 196
http://www.garmin.com/products/gpsmap196/
shows a virtual panel. Key is having the unit (any) update sufficiently fast so that making turns is not a guess. Rate of turn is easily compensated by using less than rate one turn or sufficient to keeping up with the display. The 295 is very good for this purpose.
The 295 has very good vnav function (better than the 530) so you can use it for maintaining a controlled rate of decent and the horizontal hsi steering bar indicates your deviations.
If you have an electric dg or hsi then the AI failure is less of a concern. Situational awareness keeps you out of the trees.
Bob