In heavier conditions instead of going wing and wing, would you guys choose to use just the main or just the headsail?
Depends where you are sailing and what you're after. If you are just noodling around Lake Union of an afternoon, reefed main and smaller headsail will take you anywhere. Just put a preventer or boom brake on, and accidental jibes aren't that much risk. DO remember to blow the preventer before an intentional jibe, or you will be washing your windows.
If you just want some lazy reaching-back-and-forth, deploy the big jib and keep your main in the stackpack. You'll get good speed & low stress jibes. Small mains on these boat can mean poor drive, esp. in chop. You'll need some speed on if you hope to tack thru the wind.
Big breeze, open water, long hours downwind, lots of sailors prefer double headsails anyway. Saves chafe on the main and keeps the pointy end where it belongs.
IOR boats are actually really good for this: your roller genoa (or a light blast reacher) flying to leeward, a smaller, high-clewed headsail poled out to windward. Many people will use a 100-110 for that. You can fly the second sail on an extra forestay, or on its own luff, or in the second groove of the furler (if it has one & can take the loads.) It's a bit fussy to jibe, so not a tactic for narrow waters.
IOR boats can make very good cruisers if you twiddle the sailplans a bit and don't horsewhip the boat downwind. You can actually lengthen the boom and mainsail foot w/out messing up rig balance on these boats, but most folks just do what we have planned: put a full-hoist G2 on a furler as your everyday working jib. Use a light Code0, gennaker, and/or spi for winds less than 10kts -- easy to handle, stows tight, drives the boat to hull speed. Roller-reef the G2 to stand in for the G3; add a solent or babystay to carry a staysail genoa and/or storm jib when it gets snotty. Mainsail requires little attention; many IOR owners don't reef it til ~30kts.
Here's a tentative sailplan revision for our Ballad:
The 150% G1 is replaced with a higher-aspect 138% on a furler. All our other sails are set flying -- a nylon 150 for light days (removable furler to the anchor platform), a 100% spinnaker staysail/staysail genoa for winds in the 30s, and a 50sqft storm jib hoisted flying on the spi pole topping lift. When the main needs replacing after a few seasons, we may opt for a longer boom.
a more balanced rig, but most of the boats we have to choose from in our price range are either narrow, heavy, traditional voyagers, or IOR-optimized racer-cruisers with livelier sailing characteristics but large headsail inventories. We've chosen the latter path & will spend the needed effort to minimize sail handling. It'll be fine.