What Airplane do you have? Model and tail dragger or tricycle gear?
I had metal on my first RV-4 and the big difference is they are not as aerodynamic, not as wide, narrow chord. Never had a lick of problem. I think you can make your own, but I don't think that is necessary. There are other things I would try first.
Do you have gear stiffeners. bonded (glassed) onto the gear to lower gear movement. These tapered wood strips bond and glass onto gear to dampen the spring back and spring forward whipping that can happen. This will help a lot. There are threads on this.
Crack of fiberglass fairing is the least of your worries. The overhanging prop and engine cantilevered off of engine mount and ALL gear loads, go into four bolts in firewall. This structure can, does and will crack with abuse of constant rough operation. For tricycle gear "A" models the main gear loads go into spar, but the weak link is the nose gear. Personally I would not fly off a soft "bumpy grass strip" with a trike A model. The nose gear problem has been mitigated with fixes and awareness, but the nose gear is still a potential fold-O-matic. Smooth firm dry grass, light weight, no gofer holes, sure the dash 'A' models are fine with good pilot technique.
Smoothing out the field and taxiway, or at least the 800' to 1000' of runway you use... I recommend taxi as slow as possible. Use soft field technique and takeoff in ground effect.
Bigger tires would help and they are possible without changing tire size from 5 x 5.00. 5x5.00 tire outside diameters (OD) vary by a large amount by make and model. The standard spec in many books is maximum OD of 14.1" for 5 x 500 tires. The larger OD 5x5's are typically high quality and multi ply tires. Most of the 5 x 5.00 we use are the least expensive smaller OD 5 x 5.00 (some are as small as 13.25" OD). I measured a bunch of different brands/models in a warehouse to verify this. The larger the tire the better rolling on rough surfaces, which reduces gear movement. If you have your wheel pants tight on a smaller OD tire, you might have to adjust the pants to fit the bigger OD. There is a thread where people have put larger tires than 5 x 5.00 for soft field operations (on these forums). Some are still 5" rim some 6" rim. If your field is rough this modification would be great.
Look at videos of gear movement of RV planes taxing, landing and taking off. They attach a GoPro to belly, focused on gear. it's shocking how much it moves and vibrates on asphalt runways and taxiways. I can only imagine on rough fields what they do. RV's don't have aircraft carrier landing gear, durable, plenty strong for intended use, but they're not a back country STOL tundra tire airplane. *Attn Doug: Case for RV Cub* Ha ha