4.2 is a tad too small for everyday use in Malcesine. Sure, it depends on your weight, experience and... weather, but I would suggest you to rack on your car also a 4.7 and 5.3, being 4.7-5.0 the most commonly used sizes. A 5.3, in the good sunny days, might be enough even for the afternoon wind, the Ora, in the right spots (Hotel Pier, spiaggia dei maiali), near Riva del Garda - Torbole.
To sum it up:
- Peler (N) in the early morning, strong wind, nasty chop, Malcesine is the ideal spot (many spots also in the West Coast: PrÓ, Campione, Toscolano when it blows);
-Ora (S) in the afternoon, medium wind, smoother water, Torbole (or the adjacent beaches) is a good spot.
My quiver for Garda lake is: 90 lt., 4.2, 4.7 and 5.3 sails. 6.0 for lighter Ora days.
Hope this helps.
Ciao from Italy!