Thanks for the replies, I'll try and respond to some of the comments.
First, I did have to straddle the ridge to get the wood supports in place, but there is no way you can reach the chimney to remove the cap or clean it from the ridge, and you have to be very careful to not actually step on the ridge cap as it won't support any weight without bending.
As for rubber shoes and walking right up the roof, this is possible with the right shoes (which I don't have) and on an ideal day and a perfectly clean roof (no water, no frost, no snow, no ice, no loose ash from the chimney). This was the first day the roof had been clean and dry enough for me to attempt straddling the ridge. The day before was frosty, and for about two months before that the roof had snow on it. We just recently had a significant thaw that brought all the snow down and it warmed up enough during the day to dry the morning frost off. In fact it snowed again that night, sort of melted the next day and today it is very frosty.
On a side note, when I was installing the metal roofing I looked high and low for a set of Wallaby shoes that have the soft rubber (crepe) soles for walking on the metal roofing, but found nothing that would work. I did buy a pair of shoes that had sort of soft soles, and they sort of worked, but as soon as they got a bit of dirt on them they lost all their traction.
The long and short of it is I was doing all this to be able to check and clean my chimney, and eventually, before I totally remove this scaffold, I plan to install some permanent metal supports for the planks and a permanent ladder on the rear side of the roof that I can access off the other flat roof which has access to my attic space where I plan to store the planks, chimney cleaning brush and poles. I'm thinking long term here, I want to have a "SAFE" way to access the chimney anytime of the year in any weather conditions.
I'm no stranger to scaffolding and working on roofs, but I have a lot of respect for metal roofs, especially when snow and ice are involved. If I wasn't as concerned with safety as I was, I probably wouldn't bother to check the chimney.
Thanks awoodman for the heads up on the paint peeling problem, that's all the more reason for me to have easy access up there, perhaps I'll be more incline to clean the chimney cap and roof regularly and hold off some off that corrosion problem.
Also been thinking I should put a screen in my chimney cap, but without easy access to the chimney to install it or clean it that wasn't going to happen, now I have that option.