can anyone recommend a person in LA area to pay to install a tricky Koetsu cartridge

The Koetsu RSP is no harder or easier than any other cartridge install, so if you have any experience in this, don't fret. On the other hand if you have no experience, now would be a good time to get acquainted with the process as those before have noted, albeit that would be one cart you would not want to destroy in a learning process. Enjoy the music

BTW, nice cart. What table/arm are you installing it on?

The one part of cartridge setup that really is tricky, at least in the sense of taking a good deal of time and skill to get it right, is VTA.

On the one hand VTA is the easiest of all. Is the cartridge body and/or arm pretty much parallel to the platter? Then you are done. 

But on the other hand very small, and I mean micro small, adjustments in VTA are pretty easy to hear. 

So what happens is, if your arm makes VTA easily adjustable, and if you try it and hear improvement, then you can spend as much time as you want getting it perfectly dialed in. Some even do this for each record. But if on the other hand your arm makes VTA adjustment a hassle, or you don't hear any difference, then don't worry be happy. 

Pretty much everything about turntables is like this by the way. Very fine adjustments in VTF, within the recommended range, make an audible difference. Every single aspect of cartridge setup is like this. Some guys throw their hands up and say here take my money you do it. Others roll up their sleeves and get the job done. The job by the way being endless- but you are the boss, you write your own checks, pay or don't pay the bonuses, and so of course its entirely up to you whether you fire the bum or give yourself a promotion.

millercarbon, CEO, President, and Chairman of the Board.
(Fired from more jobs than he can count!)

I appreciate all the encouragement to do myself but am not inclined to do so with such a pricey cartridge.  This is especially true here where my turntable add a layer of difficult in that the Townshend Rock 7 has a trough with oil that the tip of the arm sits in.  The arm is a helius omega arm that is frequently used with the townshend rock 7.  The helius and rock 7 distributor has used this combo before but not sure with a koetsu.  He believes the arm is very compatible with the koetsu cartridge but because of the pandemic is not doing housecalls for the foreseeable future.