Ok I'm not sure where exactly the disconnect is here. I said I want to "add to my PSEL privileges" - in other words I already have a Private plank license and by my figures I have all the hours already needed with exception of complex and/or multi if I went that route.
You said you had Commercial-RH-IH, not Private. And you started asking about going PP-ASEL to CP-AMES, which is a couple of jumps.
So, let's keep it simple -- adding ASEL at the Private level to a CP-RH-IH. Per 61.63(b), for this additional category rating, you must meet all the aeronautical experience requirements for PP-ASEL, but you don't need to take another written. The PP-ASEL experience requirements are, in simplified form:
- 40 hours total time - no doubt already met
- 20 hours of flight training - no doubt already met
- 3 hours of instruments in an ASEL
- 3 hours of dual XC
- 3 hours of night dual in an ASEL
- 3 hours of test prep in an ASEL
- 10 hour of solo in an ASEL
In theory, you could do the four 3-hour requirements simultaneously, and be endorsed for the test in as little as 13 hours (3 dual, 10 solo), but that's not realistic. Experience teaching helo pilots tells me that if you adapt quickly, a minimum of 10 hours of dual is more likely.
In addition, if you wish to add an Airplane category to your Instrument raing, you'll need to get 15 hours of instrument training in an airplane. Again, no written, but you have to take a practical test.
I also said
"Not really looking to work in fixed wing world but hey nothing like having options if needed right? which meant exactly that, I'm a working Commercial helicopter pilot, but hey if the need arises then I'll fly a plank (even though it would be soul crushing
)
Now we're talking about upgrading your Airplane privileges to the CP level, and there's a bunch more airplane training and solo time required -- you'll need at least 50 hours total time in airplanes, probably 15-20 hours of CP-Airplane training, and more airplane solo flying, probably another 10 hours to meet the solo night and XC requirements.
- Can the needed multi time be done dual ? (not needing PMEL first)
You can add your initial multiengine rating at the CP level, but you'll need both dual and solo time in the twin to do that, probably about 30 hours in all, but not many insurers allow trainees to take multiengine planes solo, so it's likely the solo time will be "supervised solo" with an instructor aboard monitoring, so you'd be paying the dual rate.
- does going seaplane grant me multi-land privelages?
No. You need another 3 hours of test prep, a sign-off, and a practical test for the additional class rating.
- the multi sea plane would give me high performance and complex as I understand it
Complex, yes, but not HP unless the engines are over 200HP. So, if you do it in an Aztec, you get HP, but not in a Seminole.
And I'm still confused what your objective is -- PP-ASEL or CP-AMES. Or both, in that order?
don't remember single engine land rating for rotorcraft 
