Ignore the scope for the moment...
If you imagine Line of Sight and Bore to be exactly horizontal, then you need to know the drop from the bore line to your point of impact at 35yds... depends on power. But chairgun will give you that. From that you can work out the angle in MOA. But unless your drop (including the unknown scope height) is 16 MOA, you'll have to dial it in anyway.
Better to keep optical centre, put the scope where your head wants it to be, and use adjustable mounts. Saves bashing on a calculator, then finding out your scope won't either keep optical zero where you want it (which is 55, not 35yds) and then finding mounts/rail combo that fits.
Well, that's my opinion anyway.
When dealing with MOA's you're talking fractions of a mm at the scope end in terms of angle to shift them. I cant remember what the numbers were, but a friend asked me to work out what he'd need in order to shift the scope by 20MOA or something similar and it worked out we were looking at an adjustment of fractions of a mm to keep it optically centred. Although you're looking for a larger amount, it's likely 16 MOA won't cross the pellet flight where you want to and any adjustment will be tiny... so hence the suggestion of sticking the scope where your head and body wants it to be, and adjusting it to that.