PS: I think this is more useful for MC1 than MC2.

I found the hotkeys 1-9 too far away from the arrow keys, but the 1-9 hotkeys can be life-saver, fast switching between speed for fast escape, creating castles, fireballs, possession ,etc

Best is to use the keymapper.
If we using vanilla DOSBox, then copy the dosbox.conf to dosbox-mc.conf
edit dosbox-mc.conf, set cycles to 24000 (seems best speed for low-res - I don't like hi-res coz the map dots are too tiny), add in the autoexec lines to mount CD and start netherw (magic carpet 2). find the line for mapper= and change that to dosbox-mc.map or something like that (so it's different from the default).

Create new start menu, that is a copy from vanilla DOSBox start menu shortcut. Add in -conf dosbox-mc.conf parameter.

Now, load up DOSBox, and press CTRL-F1 to see the key mapper.

I checked W, A, S, D keys. Only D (in Magic Carpet 2) is used for in-game config.
Anyway, we need to switch the keys to the arrow keys. So click W, Add, UPARROW. repeat for A, S, D.
Then vice verse for arrow keys. ie. Click UPARROW, Add, W. repeat for DOWN, LEFT, RIGHT.
NB: don't try binding SHIFT, CTRL, ALT since those are modifier keys.

I also switch the SPACE with ENTER (and ENTER with SPACE). Just encase I need to see all my spells.

In MC1, you can now have fast access to the 1-9 keys, while movement keys WASD. Use SPACE to see the map.
To select a 1-9 spell for right-mouse, just press SHIFT-#.

In MC2, the fast access spells is performed by holding SHIFT, and clicking either left or right mouse.

Thank you very much for your post.