Re:
I think I'd probably recommend going for a bigger size than yoiu would do for an MTB of that time.
For example, early 90's MTBs were mostly XC machines and were meant to be raced fast, so most were bought with a view to attaining that 'arse up, head down' riding position.
In fact on both of my Orange P7s (94/5 and 99) the bars are lower in relation to the saddle height than on my road bike.
This is partly due to the pretty much level top tube and the fact that you needed the clearance for your 'gentleman's area' in the event of a sudden stop.
If you're not going to be riding it aggressively off road, then you can probably afford to get a bigger bike and will be, IMHO, more comfortable for longer rides.
Alternatively, you could fit a longer stem, but I always find these look odd.
More modern bikes have sloping top tubes and relaxed head tube angles to get the bars higher up, but still leave you plenty of room for the twig and berries while standing over the bike.
The other thing to consider is the dreaded bar ends - if you're going to be riding for any length of time, then having multiple positions for your hands is prefereable to avoid numbness.