As for the clen, if you would explain the reason why you wish to be using it then it would be easier to answer. I would personally say take it 3-4 days before ending the dbol. Providing you dont jump in at 140mcgs / day and instead take the time to taper up those 4 days will not cause any health concern. Drink plenty of water and use a mutli vitamin mineral two to three times a day.

Hope this helps but is just my opinion.

Answer to your questions:

I have been on Dbol and got great gains. I need to reduce BF so as this is the last 4 days of Dbol i wanted to start introducing the Clen to my system. I am doing CV in the morning and still heavy on the evening. I am eating clean and intend to cut starting at the end of the Dbol.
After cutting for 4 weeks i will have 4 weeks off then repeat.

I have just started training again (last 3 months) and with memopry and dbol all is going weel. I want good gains rather than loads of water so this will see me through until late in the year. I can then look at a proper cycle and will not have the need to bulk and cut at the same time.