Mexiquite, contact Lee Valley about your issues. They need to hear about problems and are generally quite responsive. If you don’t hear back, post here as I’ve got Rob Lee’s email somewhere should it be necessary. He also frequents the handtool section of woodnet.net so you can post there to reach him direct.
And item 2 above is the best way to deal with “too small” base issues from ANY brand router plane (or electric spinny-beast too). I’ve done this with the LN and Stanley routers and it works great.
I’ve not had problems with the replacement irons I bought having the “heads” come loose. Definitely contact LV about that issue. Or just invest in a $3 bottle of medium strength Lock-Tite and be done with it. You can also use CA glue and either consider it a permanent fix or just apply a little heat when it is time for the threads to come loose again.