It would depend on what kind of "microlight" you have but if it was me I would install a conventional gyro based AI (what I call a "horizon").
You can pick up electric horizons for about £1000. RC Allen make some at the bottom of the quality range, Castleberry Instruments make some much better ones and those are also sold under other brand names (I think the BF Goodrich ones were actually made by Castleberry).
The horizon should be right in front of you, not somewhere to one side. It is the most important instrument in the plane, and remains important even on "100% legal VFR" flights e.g. in haze or with visibility impaired by sunlight.
Make sure it has internal illumination, for the correct voltage.
You can pick up overhauled instruments much more cheaply than new ones, from various firms in the USA. Currently I would avoid anything overhauled by Mid Continent
Of course I would also have a decent IFR GPS, which has an OBS mode so one can intercept and fly along "radials" through any waypoint. This is a super feature for things like DIY letdowns; most pilots fly NDB/VOR approaches using that mode of the GPS.
The biggest cockpit workload saver is an autopilot; even a simple 1-servo type (which can hold wings level, or fly a heading) will save a huge amount of work.