For me, I never aerate going backwards (just me). Now I will back up, get the rear standing plate almost touching house, wall, tree, etc....then once I'm back as far as I can go....step on the downward tine's pedal and go forward.
Can you go around a tree with the tines down? Yes and no. Yes, if you are going slow and it's a gradual large circle. If you turn too tight...your chains will start to click, adding stress and stretching the chains out making the hydro's jump a bit.
If it's a tight circle, I will work my way around it making an hexagon pattern. Getting as close to the object going straight, then back up and using my 30" aeration pattern as a boarder. Work my way around the tree seems like it would take a long time....but it doesn't.
I think this is where guys were breaking their belts by turning too tight with their tines in the ground. Something has to give, and usually the belts would break.
I always make a boarder along the outer part of the yard with two or three passes. Then I will start to make my mowing pattern, going back and forth. Lifting my tines once I hit my boarder area, then lifting the tines to turn around, get straight, then hit the pedal to drop my tines, aerating the other direction with a little over lap. Pretty much the same way I would cut most yards.
By going straight, you are not putting any stress on the machine or your tines.
I always will clean my tines after I get done aerating too. Takes five to seven minutes....but you will be surprised at how many rocks that get stuck in the tines.
On the front attachments, there are other companies that you can use to retrofit for the riding aerator. Just giving Toro a chance to see if and what they might make.
2013 Ford F450 Super Duty Truck
2010 Exmark Lazer Z 60" deck
2012 ExMark 30" Riding Aerator
2011 Lawn Solution Dual Hyrdo Aerator 24"
2011 Echo(backpack blower), (hand blower), (chain saw), (hedge trimmer), (string trimmers), & (tree pruner)
Craftsman 4.0 edger
2007 Big Tex 4ft metal high side 7' x 12' Trailer
2012 PJ 7' x 16' Dump Trailer
2012 Ecolawn Applicator model 200 Compost Spreader
2012 BillyGoat Force 13 Wheeled Blower & MV650SPH Commercial Vacuum