Corey,
Demagnetizing should be preformed after aprox. 30 hours of tracking.
I would recommend against the cassette type demagnetizer as they don't do an effective job of covering all the metal parts within the tape path and only address the sync head.
You would be better to buy a wand type demagnetizer as it can be applied to all the metal parts in the tapes path.
These devices are a little tricky to use for the first time user and even some experienced users who are distracted while doing the procedure.
Both Teac and Hand-dmag make good products for this application and come with full instructions that should be followed to the letter for correct usage.
Some proponents of de-magging, would suggest that there is never a need to de-mag and will testify on a bible that their machines are perfectly fine, having never used one.
I use one as a precautionary measure to ensure continued good performance from all my analog recorders.
As for cleaning the heads, Q-Tips and isopropyl alcohol are all that is required for this job. Just make sure the alcohol is 91% pure or higher as the higher the alcohol content, the less the water content and you don't want too much water around your heads!
As for TDK tape; I have had good results with their products in the past offering a good consistency of oxide coating and long life for archiving purposes.
Cheers!
