Personally I wouldn't weld washers to the LCA points. The tubes welded into the K will do a fine job of handling and spreading the load. If there had been no tubes then that area would definitely need to be beefed up. Otherwise, nice job. If you switch to a mixed gas next time you need a bottle, you'll find a HUGE improvement in your weld appearance - there is virtually ZERO spatter with a mix. Additional cost ... shouldn't be a factor unless you're a production shop. The way I look at it, the time I save not having to clean up spatter is well worth any additional cost.