For a rig, the Sprit is a decent idea. And, honestly, there are whole chapters in books
, full of viable ideas. Although my personal preference would lean toward a 2-piece, freestanding one. Much akin to what's on the PT11 dinghy
That way, when the breeze is a bit much, the rig automatically spills off the excess.
Odds are, you could fab up something from some windsurfer spares/cast offs, for a dink of that size. Possibly even to include scrounging some hardware
, or even a boom.
And none of that stuff is hard to DIY anyway.
The perk of a 2-piece mast
being, everything should fit/stow into the dink pretty easily. But be tall enough to catch enough breeze to move you when the wind's light. As seen on the PT11's vid's on youtube.
There's no need to handicap your dink with an undersized rig or sail.
As to leeway prevention, to some degree, you can prevent it by the use of a well shaped, oversized rudder
(a counter balanced one). That, & of course, there are the other options, already described.
But even an oar, properly rigged up/manipulated, does wonders for this. And too, proper weight placement is HUGE. Though as to where, depends on the dink's hull
shape (CLR), your sailplan's CE, & point of sail.