Congrats on the LA-1!!! Would love to see some pictures...

The Bolly Book is Awesome!! grotto2's info as well...Plus I've attached a copy of the OS Hanno Special manual which has some good info on tuning too (forget the OS specific stuff)...Pay close attention the the "Pipe length-vs-Needle valve" comments as those are key in my opinion!!

Here is some of my personal YS 61 info which may help get you started:

Provided you have the "standard" YS 61R LS (YS0090) then 12x8 to 12x10 on the prop will be good...I personally like the 12x10 which turns @ 10.5k using YS 20/20 fuel, you will probably turn up a bit more with the 30%...The 12x8 just spins up a little too much for my tastes...Now if you have the "AR" version (YS0091) it will swing a bigger prop...

I can tell you my personal starting point on YS 61 pipe length is 20.5"... I measure from the glow plug to the first baffle (ie: the first weld on the Hatori 650 pipe aka: Y00030)...I will shorten from 20.5" in the 1/4" increments as suggested above and normally wind up @ 19.7" as my final pipe length...I'm sure your measurements will be different, I just listed mine for reference...

Good Luck and have fun with your LA-1