I have always used PARK-2, the safest and easiest position from which to mount or dismount my RC-14.5 inch truss OTA – when I have to.
I also use that position with a much lighter OTA, such as a Questar-7 MAK.
However, although I fully agree with all the comments about the position, and especially use of OTA safety handles as Chris mentioned, having to lift it unassisted, I still don’t trust my grip even on the lighter scope. An OTA can become VERY slippery, after a night’s session, when slicked with dew or ice crystals. Similarly, even though I can still “manage” gripping maybe an 80 lb. OTA, at my age, I always like a bit of insurance, especially when standing on a step-stool.
When I need to attach or remove the OTA, I always tie (or “safety-clip”), a rope around its ends, or OTA ring handles if it has them, and hang the loop about my neck – just in case.
If I accidentally trip or fall, I have health coverage – but the scope is uninsured with possibly a long AP replacement “wait-list”, so I would rather be the one cushioning its fall. Besides, I always feel that some day it might slip from my hands, or ice cold fingers, and a belt or a rope loop, gives it a “fall-back” position. With your neck & shoulders providing that extra “third lifting balance point”, you also won’t strain your arms, whose unexpected spasm might drop it. Taking a stance on the ground like a weight-lifter, I can then deftly “lift & snap” the OTA safely into the waiting D-Plate carrier, holding it there at PARK-2, braced with one hand as I quickly secure the lock knobs. If my fingers should fumble anytime during the process, that neck belt is still there, until the OTA is safely on the mount, or down inside its travel case.