I hadn't thought about reducing the .wav file volume for the intros and beeps. However, I also have a lot of games that I would like to have quieter than my CD's, and I'm not about to hunt down and reduce the gain on all those. Likely I'll just get used to using the volume control.
Okay, I think I have this down, now, but if you would be kind enough to look at the attached screenshot and confirm.

This album was originally at about 93db, and all but the last track indicate clipping (but it is likely okay). Originally, MP3Gain had a target value of 89 and showed about a 6db cut on each track and the clip(track) (4th column) was empty. As you can see, I set a target value of 94db, and the last track now gets a 3db boost, and shows clipping, which is likely bad. The 5th and 6th tracks get a 1.5 db reduction and no longer clip. Tracks 2, 3, 7, and 8, get no gain adjustment, and still clip, but this is likely acceptable.
Question - Tracks 1 and 4 were clipping originally and now get a 1.5 dB gain and still show clipping. I am guessing this is now not the okay clipping, but likely the "bad" clipping since the gain was increased. Correct?
As I see it, my options are as follows:
Leave target volume at 89db, this will eliminate clipping on most all the albums, but they will be fairly quiet, and I will need to rely on my PC or car amp to get the volume I desire out of them.
Set target volume at 94. This will make all albums pretty loud, but in some cases, I will introduce "bad" clipping, like above. In this case, I could reduce the target volume until the 4th column no longer showed "Y", but this would make this album quieter than others that did not clip at 94db, and thus reduce the intent of MP3Gain normalizing all CD volumes.
Target Volumes between 94 and 89 would be a trade-off between how loud I can set my average volume, and how uniform the volume would be. IOW, higher target volumes mean overall all albums are louder, but there is more variation in volume, b/c some albums won't be able to reach the target without clipping, so their target value will be lower. Lower target values will mean more albums can reach the target without clipping, but the overall volume will be lower.
What I might need to do is test record a track with the gain at 89, 89.5, 90, 90.5 . . . 93, and then test this on a car deck and see when the CD volume is closest to the FM volume, and try to set this as a target. (And/or pick a target and then see how many times I have to reduce it and to what level, and then let that be my new target. For example, the example above shows no clipping at 91.6, but does at 91.7, so if the majority of my albums could handle 91dB, that would be a "safe" or reasonable target.
Did I blatantly miss anything?