Your HEQ5 on a pier will handle it visually and for solar system imaging, but not DSO imaging. The HEQ5 on tripod will struggle with it and it will be at the limits, over the limits, after you add rings & eyepieces and a finder. But on a pier, it will handle it better (the weakest point of the HEQ5 is the legs). I have an HEQ5 on a pier and it behaves way different than it did on a tripod, it bosses around 35lb loads like its a bigger mount than it is. Stability helps a lot. You also will need a shaft extension to properly counter-weight balance it.
That said, if your long term purpose is to use large scopes, go ahead and start preparing to buy a bigger, better mount. I would suggest you do not creep towards a 40lb mount and get a small increase in ability, but rather, look into the 60lb and 75lb class mounts as the only upgrade pathway, so CGX-L and CEM60 maybe and just save towards one and put it on a pier and then enjoy any size scope you can get your hands on and hoist comfortably.
Consider the moment you put an APO on there as a finder or guider. Throw on a heavy eyepiece. You're well into the 40+lb weight ranges. So go bigger.
Alternatively, big reflectors are super awkward on EQ mounts visually. That's more an imaging thing. For less money, you could get an Equatorial Platform that will track with it and set it up on a Dob/Alt-Az base. These handle way more weight and it will be far more comfortable and natural to visually observe with.
I regularly punish my HEQ5 (Sirius) with way more weight than its supposed to handle, but its pier mounted, and it makes a serious difference. I image this way routinely, for years now, often. But not DSO. This is for solar system imaging (solar mainly). Shaft extension is necessary to get the weights on there enough to counter balance and then it handles it great. Trying to do it with more weight on the shorter shaft and it bounces around because its not completely balanced. So I added a 6~8" shaft extension and it handled it great.
Here's an all quartz 200mm F6 with an 80mm F5 on the back and another 10lbs of narrowband filters on top of all that. Handles it fine, around 35lbs total, maybe more.
Here's a heavy Meade 10" F10 SCT with accessories, topping out over 32+lbs as well. Handles it even better because it has less of a moment arm.
Anyhow, I still highly recommend you go for a 60lb or 75lb class mount instead of slowly creeping up only 10lbs to a 40lb class mount. Overdo it by a lot and do it only once. The HEQ5 is great for what it is, but you will easily end up with a bigger than 250mm aperture after this and you will absolutely need more mount eventually. You will put an APO on that reflector and weight just goes up up up.
Edited by MalVeauX, 18 August 2019 - 09:28 AM.