The LAS/TAC's are excellent and are a very strong laser, the beam is slightly larger than the OTAL's but the overall performance is every bit the equal. The longer runtime is a bonus as well as the various activation solutions, not to mention the excellent prices.  

The downside will be the mount options, the Viking mount wouldn't be the most suitable choice, it's fine for a light but it isn't ideal for a laser.  You can use a Warne offset adapter to come off 12 o'clock but it won't be tucked in as close as the OTAL or Viking (pic).  

It will be higher than the Warne offset but it would be a solid mount.

Quoted: What about those YHM 45 degree rails? Basically, what would be the best possible arrangement you would recommend with price no objection?

The YHM offset mounts will be higher than what's desired.   Truthfully, you'll have to with the Warne offset mount or try the Viking Tactics mount.  Otherwise, just go with the OTAL.

Quoted: Calvin, I called last week about a laser for the PS90.  How long are the wires on the straight and coiled pressure switches for the Las/Tac?  I can't believe Laser Devices site doesn't say that Thanks!

The straight wire leads are 6" + the pressure pad itself.