I fly with a couple of clubs that don't require AMA membership but most the guys belong anyway just for the insurance. At any club the members will all be strangers until you go there a few times, some will be buttheads and some won't, just like anything you do.
If your having trouble with an LA engine you really better go to the club for some help and lessons. Most clubs will allow a new pilot to fly with an instructor or member standing with you until your AMA membership is activated, that usually takes a couple weeks. I remember flying at a couple clubs before my membership came through, they are pretty understanding.
I used nothing but the LA series of engines for a couple of seasons, the .46 though. I was never a big fan of the .40 but have a couple from trainers I had been given over the years. OS finally quit producing the .40, it was way under powered compared to the .46 but it will work on a lot of trainer type of planes and anything not requiring a lot of pull.
Learning to tune an engine is better learned with a hands on instructor then on a web site. We all have our own ways, Johns pinch testing is a very popular one and it works very well. He has posted the how to several times over the years but a hands on instructor will be able to tell if you have the low and high ends adjusted correctly.