Please, call me Erich.

Here's my 21 day Clen cycle:

Daily Dosages Listed
1. 20mcg AM
2. 20mcg AM
3. 20mcg AM & 20mcg PM
4. 20mcg AM & 20mcg PM
5. 40mcg AM & 40mcg PM
6. 40mcg AM & 40mcg PM
7. 40mcg AM & 40mcg PM
8 40mcg AM & 40mcg PM
9. 40mcg AM & 40mcg PM
10. 40mcg AM & 40mcg PM
11. 40mcg AM & 40mcg PM
12. 40mcg AM & 40mcg PM
13. 40mcg AM & 40mcg PM
14. 40mcg AM & 40mcg PM
15. 40mcg AM & 40mcg PM
16. 40mcg AM & 40mcg PM
17. 40mcg AM & 40mcg PM
18. 40mcg AM & 40mcg PM
19. 20mcg AM & 20mcg PM
20. 20mcg AM & 20mcg PM
21. 20mcg AM

Sometimes, I might add another week for a total of four weeks of Clen.

I've always gone with the 2 on/1 off split. No problems with building a tolerance?

I haven't experienced building a tolerance..

I've also used a 2 on 1 off split like you posted, and gotten good results.

When cycling for longer, I'll often run Clen and Ketotifen (Keto) conjointly.

I base what I'm about to write next on no solid scientific foundation, just my own personal experience, and that is that I think some variance in how you cycle Clen can be a good thing. The longest I've run Clen was 5 weeks, with a Pyramid up to 100mcg's day (for a total of 10 days of 100mcg's, then pyramid back down), split 50mcg's AM, and 50mcg's PM.

However, that's JMHO.................E