Spot Welds on Roof - '70 Charger R/T

[pirateDan]

Tried doing a search on this subject, but couldn't find one.  So apologies if this is redundant.

Am in the process of helping my son to restore a 1970 Charger U-code 440 R/T, which had vinyl top.  Unfortunately, the roof skin has developed a terminal case of vinyl top cancer and needs to be replaced.  Just discovered this when visiting the media blasting shop today.  My question is the spot welds on the roof line don't look like normal "round" spot welds, but they are little 5/6" to 3/8" up and down (sometimes slanted) hash marks/lines about one inch apart.  Unfortunately, I didn't have my camera with me when I was at the blasting shop, but they sort of look like this:   |   |   \   |   |   /   |   

Is this normal?  Also, any suggestions on the size of spot weld cutter to use?

Any help will be greatly appreciated.

[sardillim]

i have also seen this in other parts of the car (were the inner and outer wheelhouse are joined)  very difficult to separate.

[Monziac]

I just finished skinning my roof. I used a 3/8" cutter. Many cases I used a 3 air cut off tool to grind it down. I would grind/cut off a few then use a hammer and a paint scraper to get under and break the weld. Cut off most of the inner roof and get it out of the way, so you are only trying to remove small strips around the sides. Patience is a virtue!

Jon