RE: servos
Jim,
the 8231 is a great pattern servo. If you are looking more for a budget servo look to the 811 digital that JR sells. These are very good servos with regards to centering and precision. They will not be as good as the 8231 but then again they are less than $50 each.
The 8231 is a coreless servo this refers to the type of motor and coreless are smoother and more precise. However I have used the 811's with really good success in some sport type pattern models. I like them. The 811 is in my opinion basically the top of heap as a sport servo. After this you are getting into the higher dollar higher performance servo.
I personally feel having run most of what Fut and JR have to offer in this performance and price range that the 811 is the best kept secret out there.
Saying all that. Servos are the link to you and the model. So I would say buy the best servos that you can afford for a pattern model. If $50 each fits the budget then go for it. If can swing a little more try the 8231's. Another option is to go with a high performance analog servo. The 8101 from JR or the 4131 are extremely tight precise servos but are basically the generation before digitals. These are priced at a few dollars more than the 811's but not as high as 8231's
Just because they are analog doesn't mean they are not as good as a digital anything. The precision of the analog 4131 won some TOC's back 10 years ago or so. They are good servos.
Another thing to consider is high performance servos tend to last a really long time. If you get coreless versions then a new pot and new gears is all that is needed to make the servo like new again. So these servos can serve you for years to come. I personally have 8231's that are 6-7 years old and have been in 3 different models.
Allen