It would help if you could submit your www.tvfool.com
RESULTS so we can assess your OVERLOAD situation....and I could make some predictions for which FM and TV Stations would be affected the most. Since a typical RG-6 Coax has a "typical" Loss of about 2 dB/100-ft in FM Band, the RF Splitter Loss would presumably be the primary reason to justify passing FM Signals thru a Preamp/DistroAmp. However, note that using a Preamp/DistroAmp to provide an extremely Low Noise Figure isn't all that important in Lo-VHF/FM Band since Man-Made Noise is typically many dB Stronger than Thermal Noise, so you may or may NOT see any improvement in FM Reception....and will LIKELY see Degradation to Next Adjacent Channel Rejection (etc) due to the Intermod Products generated throughout the FM Band, which a "naked" FM Tuner would have minimal if any problems meeting "specs":
[Man-Made Noise in Excess of Thermal Noise]
Winegard LNA-200 has a spec Gain of 18 dB, but Calaveras measured 14 dB Gain in VHF Band (presumably also FM), but Overload Resistance isn't as high as it COULD be. I have NOT seen any LNA200 measurements for Gain in FM Band, which in many Preamps can be MUCH MORE than mfr "spec" number....or ATTENUATED, like in RCA TVPRAMP....perhaps others have more specific info??? We need to see your TVFOOL and FMFool Results to make sure, but I suspect that 18 dB LNA-100 MAY have TOO MUCH Gain, making it more susceptible to Overload Desensitization [or FM Band Attenuation???]....you would be better served by using 15 dB Gain CM3410 [may be used outdoors], with significantly higher Overload Resistance.
Although some FM Stations are co-located with TV Stations....in the many FMFool Results that I've looked at, MANY/MOST are peppered across the landscape, resulting in Strong Stations frequently being much closer than TV Stations...and they end up with signals of all different strengths coming from MANY Different Directions. Which means 2nd Harmonic of strong FM Stations can interfere with reception of TV Stations in Hi-VHF Band (Ch7-13)....and in some unusual situations can also affect some UHF Band Stations.
I recommend AGAINST using a Combo VHF/UHF Antenna to ALSO feed your FM Radios: 1) As I said, you likely have FM Stations in MANY different Directions, which would require rotating that Combo very frequently, usually in a DIFFERENT direction than needed to ALSO receive desired TV Station, 2) Strong FM Signals can result in 2nd Harmonics preventing reception of weak Hi-VHF Band TV Stations, 3) If you pass MULTIPLE Strong FM Signals thru a Preamp/DistroAmp then the Intermodulation Products among those signals can prevent reception of some Weak FM Stations, 4) GOOD, Low-Loss Band Splitters that separate JUST the FM Band (88-108 MHz) from IN-BETWEEN the Lo-VHF (54-88 MHz) and Hi-VHF+UHF Bands (174-698 MHz) are rare...and fairly expensive....fortunately if you aren't feeding both TV and FM in the SAME Room, you wouldn't need one in that location, and 5) In order to separate out the FM Band, the Tin-Lee S7-TF can't help but attenuate portions of the adjacent Ch6 TV Signal (82-88 MHz), as well as 1.4 dB attenuation on Bottom part of FM Band (88 MHz) and 2.5 dB attenuation on Top part of FM Band (108 MHz):
I ALSO recommend AGAINST combining an FM Antenna with whatever you use for TV Reception, even if combined on the OUTPUT of the TV Preamp to reduce 2nd Harmonic and FM Intermod Distortion....for same reasons as above....PLUS you are going to need one more of those expensive Tin-Lee S7-TF TV/FM Band Splitters to combine the FM Antenna with your TV Antenna(s).
What I DO recommend is to use a separate Coax Downlead and Distribution System for a PAIR of FM Antennas....the first being a Low-Gain TRUE-OMNI (i.e. Double-Hoop type) which would be the Primary Antenna signal. And if you want to listen to even weaker FM Stations, a dedicated medium to high Gain FM-Band Antenna (on a Rotator) that goes thru an A/B FM Switch to feed either just one "favored" FM Radio or perhaps the entire FM [or TV?] Distribution Network....or a THIRD FM Distribution Network to each room. FYI: Radio Shack made an A/B RF Switch with IR R/C...which could be part of a whole home IR Distribution Network.
[Double-Hoop (c) is TRUE-OMNI....most others, incl. Turnstiles, are Bi-Directional with NULLS]
[R-S may not exist anymore]
[Pricey used units.....]
Feel free to do whatever is easiest for you....just be aware that more $$$'s can yield more benefits....if you even care....
As a bare minimum, you might want to Combine the Stellar Labs Double-Hoop FM Antenna with your existing TV Antenna using a Tin-Lee S7-TF....plus at least one more for your Primary TV+FM listening room. This would supplant the Directional FM Gain [IF ANY] of your existing TV Antenna(s), with the Double-Hoop's TRUE-OMNI Gain in ALL Directions, so it wouldn't MATTER which way the TV Antenna is pointed.